# Helium Atomic Number













	98 (fluorine). Since the atomic number of Be is 4, and the atomic number of Helium is 2, you would add four plus two, which equals six. Each element has a symbol, which is a one- or two-letter abbreviation of its name. But it does not form a diatomic molecule like hydrgen (H2) does. Helium is a chemical element with the symbol He and atomic number 2. Janet's original left-step table leads to the loss of a perfect atomic number triad, in moving helium out of the noble gas group, whereas this new table retains the helium triad. Hence, helium is grouped in the list of inert gases. A pumped bath of liquid helium 3 can be used to cool down to about 0. Helium is the element whose atomic number is 2. ) Temperatures in excess of 10,000,000 °K are usually needed. The term "atomic radius" is not particularly helpful although its use is widespread. Atomic dimensions and structure: Atomic Radius: 31 pm: Covalent Radius: 28 pm: Van der Waals Radius: 140 pm: Crystal Structure: Face-centered Cubic: Lattice Angles. Lecture 4 Hydrogenic ions. The atomic number gives the “identity” of an element as well as its location on the periodic table. #Glogster #Helium. 000 137 % as determined by Nier had a negligible effect on the atomic weight of helium. 0026; a colorless and odorless gas. 	Natural helium consists of 3He and 4He stable isotopes. what happened to the indivisible atom part of dalton's atomic theory, and why?. Number of Atoms (n) and Number Density (N) The number of atoms or molecules (n) in a mass (m) of a pure material having atomic or molecular weight (M) is easily computed from the following equation using Avogadro's number (NA = 6. The most important chemical properties of helium include its atomic mass, state of matter, boiling and melting points, and density. Helium is both the second lightest and second most abundant element in the universe. Atomic Mass and Atomic Number Worksheet - Key Name of Element Symbol Atomic Number Atomic Mass Protons Neutrons Electrons copper Cu 29 64 29 35 29 tin Sn 50 119 50 69 50 iodine I 53 127 53 74 53 uranium U 92 238 92 146 92 potassium K 19 39 19 20 19 lithium Li 3 7 3 4 3 oxygen O 8 16 8 8 8 gold Au 79 197 79 118 79. Working with triads A triad is the name given to a group of three elements falling vertically in any group of the periodic table. A helium atom is an atom of the chemical element helium. Once you have found the number of valance electrons, place them around the elements symbol. This number of protons is so important to the identity of an atom that it is called the atomic number of the element. 008 2 IIA 2A 13 IIIA 3A 14 IVA 4A 15 VA 5A 16 VIA 6A 17 VIIA 7A 2 He 4. What is the atomic mass of mercury? 3. The mass number measures the number of protons and neutrons in the nucleus of a particular atom. The existence of Helium-3 was first proposed in 1934 by the Australian nuclear physicist Mark Oliphant. Credit for this discovery goes to Swedish chemists Per Teodor Cleve. Search for crossword clues found in the Daily Celebrity, NY Times, Daily Mirror, Telegraph and major publications. 999 16 2 Helium 3 Carbon. First of all, we will look for a few extra hints for this entry: Helium's atomic number. 		The mass number of Helium Atom is 4. It is classified as an inert gas; atomic number – 2; atomic weight – 4. Helium is much more than your ordinary trampoline park, we offer the best of trampoline park experience with a host of incredible indoor adventure attraction options. Should we ban helium balloons?  They argue the impure helium gas used for balloons is not the same as the liquid helium used for the MRI market, and is a byproduct of supplying liquid helium. Name two noble gases 8. Molecular orbital theory is more powerful than valence-bond theory because the orbitals reflect the geometry of the molecule to which they are applied. Atomic mass unit definition is - a unit of mass for expressing masses of atoms, molecules, or nuclear particles equal to 1/12 the mass of a single atom of the most abundant carbon isotope 12C —called also dalton. It is the same as the number of protons that the atom of each element has, so sometimes atomic number is called proton number. c '' Students know  atomic number greater than that of. The outer shell of helium does not have an atomic number, that number belongs to helium itself whose atomic number is 2. Helium is an element that has the atomic number 2 and is a gaseous substance. One mole of molecules = Avogadro’s constant number of molecules. Because we can find the number of protons and the atomic mass of an atom by looking at its element information in the periodic table, we can calculate the number of neutrons in that atom by subtracting the number of protons from the atomic mass. We have 1 answer for this clue. In a hydrogen bomb, two isotopes of hydrogen, deuterium and tritium are fused to form a nucleus of helium and a neutron. Areas covered include atomic structure, physical properties, atomic interaction, thermodynamics, identification, atomic size, crystal structure, history, abundances, and nomenclature. Lastly, the number in the bottom of each block is an elements atomic mass number. Working with triads A triad is the name given to a group of three elements falling vertically in any group of the periodic table. It is identical to the charge number of the nucleus. 	The 18 th group of periodic table of elements is meant for placing the symbols of all inert gases. Protons have a charge of +1, and a mass of approximately 1 atomic mass unit (amu). The boiling and freezing points of helium are lower than those of any other known substance. A major characteristic of an atom is its atomic number, which is defined as the number of protons. As an example, consider helium with one electron excited into the 2s state (and the other left in the 1s ground state). 002602 amu Melting Point:-272. The Helium atom. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. The atomic number of helium is 2. Chemistry Questions & Answers for Bank Exams,GATE, Bank Clerk,Bank PO : Atomic bomb is based on which of the following principle?. All structured data from the file and property namespaces is available under the Creative Commons CC0 License; all unstructured text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. The light atomic weight of helium, in conjunction with its inert properties and the fact that it is considerably safer to store than hydrogen, makes it a popular choice for gas chromatography across a range of life science and medical uses. Each element's atomic number, name, element symbol, and group and period numbers on the periodic table are given. 00 amu/atom or 4. Hydrogen and helium are the smallest elements and these are the first two elements in the periodic table. 204 X 10 ^24 electrons. A supersonic atomic gas-jet target is prepared and crossed with the antiproton beam. It is the second most. 		The Department of Energy's Jefferson Lab uses large amounts of liquid helium to operate its superconductive electron accelerator. This produces moscovium which alpha decays rapidly into nihonium. Element Groups: Alkali Metals Alkaline Earth Metals Transition Metals Other Metals Metalloids Non-Metals Halogens Noble Gases Rare Earth Elements. Since they do not react easily participate in chemical. All elements are composed of tiny, indivisible particles called atoms. Helium atom is created by two Hydrogen's atoms which are the smallest, basic, stabile, unclosed quantum, wave-particle formation. According to Wikipedia, the great online dictionary, and I quote: "It is a colorless. The density is 101. CAS number. , helium-4), and the particles required to embody the fields of quantum field theory (e. A helium atom is an atom of the chemical element helium. 587387 eV) Ref. The helium atom has two electrons so that, once again, the atom as a whole is neutral. Europium-151 has an abundance of 48. An alpha particle (helium nucleus with atomic number 2) has an initial kinetic energy of 8. As a result, helium is one of the least reactive elements on Earth. Re: Can helium exist with less than 2 neutrons? « Reply #5 on: 27/09/2012 15:29:25 » Yes the atomic number defines the number of protons but the atomic weight the number of protons plus the number of neutrons so subtract the atomic number from the atomic weight of an element and you get the approximate number of neutrons. Beginning with the orbit closest to the nucleus and working outward, the number of electrons per orbit should be: 2, 8, 18, 18, 1. Helium's atomic number. 	The total number or protons + neutrons is called the mass number (sometimes called the nucleon number in Physics). , photons and gluons). Polonium: Atomic mass number given for longest lived isotope. Atomic Mass is has a decimal value. The star makes helium by squashing four hydrogen atoms together into one new helium atom. Therefore, Helium has 2 protons in its nucleus. Atomic Mass and Atomic Number Worksheet - Key Name of Element Symbol Atomic Number Atomic Mass Protons Neutrons Electrons copper Cu 29 64 29 35 29 tin Sn 50 119 50 69 50 iodine I 53 127 53 74 53 uranium U 92 238 92 146 92 potassium K 19 39 19 20 19 lithium Li 3 7 3 4 3 oxygen O 8 16 8 8 8 gold Au 79 197 79 118 79. Its the most abundant element known in the universe after hydrogen. Updated: 16 January 2015 We found 1 answers for the crossword clue Helium's atomic number. 4 c Periodic Table of Elements Directions: Use the periodic table to fill in the below chart. Example; What is the mass number and atomic number of the ? Solution: Mass number = 31, atomic number = 15. Silver Atom - Larger View The silver atom has 5 electron orbits (energy levels) with a total of 47 electrons. Atomic number 2; atomic weight 4. What is the electron configuration for helium?  The higher the atomic number, the further the outermost shell is from the nucleus. As t he charge of proton is +1 and the charge of electron is -1,equal number of protons and electron make a helium atom neutral or charge less. The atomic mass (number at the bottom) is the amount of protons and neutrons added together. Hence the radial probability distribution curve should contain a trough representing a radial node. Sir William Ramsey, Nils Langet, P. 		(Never inhale helium, by the way. Get the facts about element Helium (He) [2] from the periodic table. Let's find possible answers to "Helium's atomic number" crossword clue. Helium has the distinction of being the only element discovered outside of Earth prior to finding it within our planet. In its elemental form helium's CAS number is 7440-59-7. Students also assemble a. Helium's atomic number is a crossword puzzle clue. Number of Energy Levels: 1: First Energy Level: 2: Helium: Elements by Name: Elements by Number: Home: Graphic courtesy of ChemicalElements. helium (Q560) From Wikidata. An element is composed of several types of atoms. Number of neutrons = mass number – atomic number. The name of each element (in brown) is accompanied by its chemical symbol (in red), as well as its atomic number Z and its most common (or most stable) mass number A. Helium n (genitive Heliums, no plural) helium; the chemical element and lighest noble gas with the atomic number 2 Helium ist das zweithäufigste Element im Universum. It is lighter than air. number of hydrogen atoms ----- = 12. So it's right here, so there's one proton in. 	The atomic number for helium is Z = 2 because every helium atom has 2 protons. 999 % pure helium gas costs 177. Get the facts about element Helium (He) [2] from the periodic table. This is the number of protons in each atom. the number of protons only How many electrons, neutrons and protons would be found in an atom of carbon-14 (atomic number 6)? 6 electrons, 6 neutrons, 6 protons. ³ In Figure 1, we see that A is equal to 4. 9 degrees Celsius. The mass number (A = # of protons + # of neutrons) is four. Helium is the second lightest element and is the second most abundant in the observable universe, being present in in the universe in masses more than 12 times those of all the other elements. User: Helium has an atomic number of two, so its outer energy level is full. Helium only has one atomic shell, which fills up when it has two electrons. tells you the number of _____ in a neutral atom of that element. So for example if a beryllium atom (atomic number 4) went through alpha decay it would become helium (atomic number 2). Helium is a chemical element with atomic number 2 which means there are 2 protons and 2 electrons in the atomic structure. Helium's atomic number is a crossword puzzle clue. 		Each element has a unique number that identifies how many protons are in one atom of that element. Thus, hydrogen has an atomic number of 1, while iron has an atomic number of 26. As helium is cooled below its transition point, it has an unusual property of superfluidity with a viscosity approaching zero micropoises. 30% helium. By United Nature Theory. Read "Atmospheric helium capillary dielectric barrier discharge for soft ionization: broadening of spectral lines, gas temperature and electron number density, Journal of Analytical Atomic Spectrometry" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Sodium has an atomic number of 11 because its nucleus has 11 protons, while oxygen has an atomic number of 8 because its nucleus has 8 protons. Two values are given here, one is based upon calculations and the other upon observation - follow the appropriate link for further details. When helium atoms are released into the atmosphere, they rise until they escape into space. (Never inhale helium, by the way. Silver Atom - Larger View The silver atom has 5 electron orbits (energy levels) with a total of 47 electrons. It is identical to the charge number of the nucleus. In this example the atomic number is 17 and the mass number is 35. Best Answer: Atomic number = How many protons are present in an atom of the element. Helium is a chemical element with the atomic number 2, meaning that a neutral helium atom has two protons and two electrons. What is the Difference Between Helium and Hydrogen - Comparison of Key Differences. The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z). 	The atomic number and the mass number of an element is usually written in the following way: The helium atom has a mass number of 4 and atomic number of 2. Atomic structure of Iron includes atomic number, atomic weight, electron configuration. The Masss number of helium is the number of protons plus neutrons of a specific isotope of helium. All that basically means is the higher the number the heavier the gas. Element Symbol Atomic Number # of protons # of electrons Atomic Mass Rounded Atomic Mass 1 Oxygen O 8 8 8 15. The spectroscope should be calibrated at 0° by the students or by the instructor using the helium tube. Your choice, the fun is up to you. Use the Bohr models to determine the number of valance electrons. Helium (He) is the element of the 8th group of the Mendeleev's periodic table. atomic symbol Pb which stands for the Latin word for lead which is plumbum. What is the electron configuration for helium?  The higher the atomic number, the further the outermost shell is from the nucleus. Number of protons in Helium is 2. The periodic table (see figure below) displays all of the known elements and is arranged in order of increasing atomic number. The total number of protons and neutrons in an atom is referred to as the atomic mass, or M. Helium is both the second lightest and second most abundant element in the universe. Name two noble gases 8. Since they do not react easily participate in chemical. 		0°F, respectively—are the lowest among the elements. Atomic Orbits The nature of atoms and the manner in which electrons interact and move about their nucleus has puzzled scientists for a long time. the number of protons only How many electrons, neutrons and protons would be found in an atom of carbon-14 (atomic number 6)? 6 electrons, 6 neutrons, 6 protons. It is non-reactive because it's shell is full. A graph of each property versus atomic number is the best approach. Why Is There a Helium Shortage? A crucial ingredient in MRI machines, wafer manufacturing, welding, and more, helium is experiencing a shortage that's driving up its price around the world. For example, helium (with atomic number 2) has a complete first shell, while in case of neon with atomic number 10, 2 electrons fill the first shell and the remaining 8 occupy the second shell, thus making the element. 6 was found in the Er film with a Q He:Q Ar flow ratio of 18:1. "The chemistry of an atom depends only on the number of electrons, which equals the number of protons and is called the atomic number. a positron 3. There is, first of all, hydrogen--then to its right is helium. ” IsotopesTheyare those elements which have the same atomic number but different mass number. First of all, we will look for a few extra hints for this entry: Helium's atomic number. Helium is much more than your ordinary trampoline park, we offer the best of trampoline park experience with a host of incredible indoor adventure attraction options. Files are available under licenses specified on their description page. ALPHER* AÞÞlied Physics Laboratory, The Johns Hopkins University, Silver SPring, Maryland AND H. Atomic Capital receives a high number of inbound requests for our services and unfortunately can not reply to every submission we receive. UN number 1046 is for helium, compressed. Helium has an atomic number of two. 549994 K, -451. 	shows atomic number, symbol, name and atomic weight - including 2016. Bosons differ significantly from a group of subatomic particles known as fermions in that there is no limit to the number that can occupy the same quantum state. Bring a 3-1/2 inch PC-formatted diskette or a USB flash drive. What is the atomic number of carbon? (Answer: The atomic number for carbon is Z = 6, which means carbon has 6 protons. 00 amu Molar mass of helium is 4. , helium-4), and the particles required to embody the fields of quantum field theory (e. AU - Wexler, Bernard L. Enter the answer length or the answer pattern to get better results. Helium is the second most abundant element in the universe. Each atom, therefore, can be assigned both an atomic number (the number of protons equals the number of electrons) and an atomic weight (approximately equaling the number of protons plus the number of neutrons). So we're going to talk about hydrogen in this video. Aluminum has atomic number 13, helium has atomic number 2, andsilicon has atomic number 14. Janet's original left-step table leads to the loss of a perfect atomic number triad, in moving helium out of the noble gas group, whereas this new table retains the helium triad. Relative atomic mass The mass of an atom relative to that of carbon-12. Extremely unreactive, it is an inert gas inert gas or noble gas, any of the elements in Group 18 of the periodic table. The number of inert gas group is 18 in the modern periodic table. 35E+7 V (the voltage is decreasing in this region). 		Helium's atomic number. A major characteristic of an atom is its atomic number, which is defined as the number of protons. The atomic number of the elements represents the number of electrons the element has. Return items starting with number. Atomic weight of Helium is 4. As with any grid, the periodic table has rows running left to right, and columns running up and down. Number of neutrons = mass number – atomic number. 008 2 IIA 2A 13 IIIA 3A 14 IVA 4A 15 VA 5A 16 VIA 6A 17 VIIA 7A 2 He 4. Atomic Symbols: The atom of each element is made up of electrons, protons and neutrons. This means that each of these atoms has:. 028 seconds. The way find this number is by looking at the periodic table, and it will be listed as the second one. Helium is a place that helps you create fabulous memories. The gaseous element also has an atomic number of 2 and an atomic symbol of He. To change uranium to barium meant a decrease, in atomic number, of 36! It was as though the uranium atom had broken more or less in half ( uranium fission ). We last saw this clue in The Boston Globe Daily Crossword on 6 August 2016, where the answer was 'TWO'. The main helium source in the world is a series of fields of natural gas in the United States. Helium has two electrons in total, and according to the aufbau principle, it adopts the electronic configuration $\mathrm{1s^2}$. 	The abundance of hydrogen and helium, i. The question then is, how many grams of helium fit in one mole? This is the molar mass of Helium gas and happens to be 4. The chemical symbol for Helium is He. Helium is mono-atomic (one atom per molecule) so the atomic mass of Helium is used: 4. The result is an element with atomic number two less than before. The periodic table (see figure below) displays all of the known elements and is arranged in order of increasing atomic number. The nucleus of the atom of the element helium (He) has two protons (hence helium has an atomic number of 2) and two neutrons. No two elements have the same atomic number (or the same number of protons), so the atomic number identifies the element. All atoms of the same neutral element have the same number of protons and electrons but the number of neutrons can differ. Diagram of the nuclear composition, electron configuration, chemical data, and valence orbitals of an atom of helium-4 (atomic number: 2), the most common isotope of the element helium. Astatine: Atomic mass number given for longest lived isotope. Eventually, a point is reached beyond which there are no stable nuclei: the bismuth nucleus with 83 protons and 126 neutrons is the largest stable nucleus. Atoms of the same element can have different numbers of neutrons, however. The number of protons in an atom is called the atomic number (sometimes called the proton number in Physics). Its atomic number indicates there are two electrons and two protons in a neutral helium atom. So, we have seen the k -shell being filled with electrons in helium. Notice that there is one and only one integer from 1 - 110 or so in each element box, so we have found all the elements. The abundance of 3 He in air of 0. There is, first of all, hydrogen--then to its right is helium. Electron configuration, atomic weight, melting point, boiling point, and other standard physical data for the element helium (atomic number 2). 		Janet's original left-step table leads to the loss of a perfect atomic number triad, in moving helium out of the noble gas group, whereas this new table retains the helium triad. This is the total number of protons plus the number of neutrons (i. This helium presumably has its origin from alpha decay in the radioactive material. The chemical properties of an atom are determined by its atomic number and is denoted by the symbol Z. What is the Difference Between Helium and Hydrogen - Comparison of Key Differences. Its atomic symbol is "He," and its atomic number is 2 on the periodic table. Because we can find the number of protons and the atomic mass of an atom by looking at its element information in the periodic table, we can calculate the number of neutrons in that atom by subtracting the number of protons from the atomic mass. So for hydrogen, hydrogen's atomic number is one. Helium (He). Helium can be made solid at room temperature if the pressure rises to about 114 thousand atmospheres: that is a pressure of 1. What is the atomic number of carbon? (Answer: The atomic number for carbon is Z = 6, which means carbon has 6 protons. Helium is much more than your ordinary trampoline park, we offer the best of trampoline park experience with a host of incredible indoor adventure attraction options. It is the second most. Atomic weight of Helium is 4. As a result of this, though very light in atomic weight, lithium is less common in the Solar System than 25 of the first 32 chemical elements. The total number or protons + neutrons is called the mass number (sometimes called the nucleon number in Physics). Find answers for the crossword clue: Helium's atomic number. Helium-3, also written as 3 He, is a light isotope of helium having 2 protons but only one neutron and an atomic mass of 3. Students also assemble a. 	” IsotopesTheyare those elements which have the same atomic number but different mass number. Atomic mass vs Atomic number. Schrodinger Equation and Variational Calculations The Schr˜odinger equation for He atom, again using atomic units and as-. 03% and Europium-153 has an abundance of 51. The number of protons in a given atom's nucleus is called its atomic number, and it is these atomic numbers by which the elements on the periodic table are classified. Langley and P. Below are the different uses for helium that you probably didn’t know existed. This means it has two electrons in s orbitals with a principal quantum number of 1. Helium is a rare, clean and inert gas. This is the number of protons in each atom. 1785 g/cm 3 Color: colorless Atomic Structure. First of all, we will look for a few extra hints for this entry: Helium's atomic number. Fundamentals; 1. Helium | He | CID 23987 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards. Each element has unique properties that differ from the properties of other elements. Adding a heat will convert the solid into a liquid with no temperature change. Interesting facts: It is created as a result of radioactive decay. It then enters a region of space where the electric potential changes by an amount 1. Thus, #Z#, the atomic number #=# #2#. Helium Facts - Atomic Number 2 or He 1 This entry was posted on May 18, 2015 by Todd Helmenstine (updated on December 27, 2017 ) Periodic Table cell for the element Helium. 		Atomic Number of Helium is 2. According to this, the atomic orbitals $2s$ and $2p$, that are at the same energy in the case of hydrogen atom, are no longer at the same energy for the atom of helium. Each entry has a full citation identifying its source. Notes: The spectroscopic data below are for the isotope 4 He. Helium can be made solid at room temperature if the pressure rises to about 114 thousand atmospheres: that is a pressure of 1. Diagram of the nuclear composition, electron configuration, chemical data, and valence orbitals of an atom of helium-4 (atomic number: 2), the most common isotope of the element helium. And you can find the atomic number on the periodic table. 2 K (19 atoms/nm 3). Best Answer: Atomic number = How many protons are present in an atom of the element. Melting point of Helium is -272,2 °C and its the boiling point is -268,9 °C. Below is Lithium (Li), it has 3 protons in the nucleus and 4 neutrons. Chemistry is simply numbers, an idea Pythagoras would have liked. Next on the. Find the weight of the given amount of gas, find how many moles it corresponds to and then find the number of atoms. The atomic weight of He is 4. The nucleus of the helium atom contains 2 massive, positively charged particles. Helium atom {a particle of nucleus} is the most stabile formation. It is used in balloons, deep sea diving and welding and in very low temperature research. 	The atomic number (number at the top) is the amount of protons and the amount of electrons. Helium - Atomic Number. Helium is a colorless, light, monoatomic noble gas. Clue: Helium's atomic number. Energy levels in beryllium atom. So, we have seen the k -shell being filled with electrons in helium. According to this, the atomic orbitals $2s$ and $2p$, that are at the same energy in the case of hydrogen atom, are no longer at the same energy for the atom of helium. Mass number and atomic number. The neutron also is located in the atomic nucleus (except in Hydrogen). , Ag for argentum, Pb for plumbum, Au for aurum). 1786 kg/(m^3) Helium has an atomic mass of about four times that of hydrogen. This fusion releases 17. The 18 th group of periodic table of elements is meant for placing the symbols of all inert gases. It then enters a region of space where the electric potential changes by an amount 1. How dose the atomic mass and atomic number compare for heliumA: helium does not have an atomic numberB: the at… Get the answers you need, now!. helium (contents): 0. Notes: The spectroscopic data below are for the isotope 4 He. Helium is both the second lightest and second most abundant element in the universe. Helium has Atomic Number 2 and is a colorless, odorless, tasteless, and non-toxic inert gas. 		Since the atomic number of Be is 4, and the atomic number of Helium is 2, you would add four plus two, which equals six. It consists of a nucleus of two protons and neutrons, and two electrons in atomic orbits. 1785 gram per liter. Silver Atom - Larger View The silver atom has 5 electron orbits (energy levels) with a total of 47 electrons. Name: Helium Symbol: He Atomic Number: 2 Atomic Mass: 4. 2 ppm by volume in the atmosphere) because nonreactive helium is light enough that it can escape Earth's gravity and be lost to space. But it does not form a diatomic molecule like hydrgen (H2) does. However, the element is rare on Earth (5. Helium's atomic number is a crossword puzzle clue. Helium is the second most common element in the Universe (after hydrogen), making up around 24% of its mass. The structure of each of the other kinds of atoms follows the same. However, the uses for helium go far beyond just a few novelties. But group 2 elements have incompletely filled valence shell with 2 valence electrons. This list contains the 118 elements of chemistry. helium, He, atomic number 2 (noun) a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas and Kansas) Synonyms: helium, atomic number 2. A)neutral B)inert C)an anion D)a cation. There is, first of all, hydrogen--then to its right is helium. The nucleus consists of 2 protons (red) and 2 neutrons (orange). 0 20406080 100120 0 50 100 150 200 250 Melting Point vs. 	If an atom doesn't have a filled shell, it will be chemically. It is the second most. The last (and only) level of helium's electronic configuration is $\mathrm{1s^2}$, and therefore $\ce{He}$ has 2 valence electrons. Atomic Number. According to Wikipedia, the great online dictionary, and I quote: "It is a colorless. Commercial helium is extracted from natural gas. For example, hydrogen has an atomic number of 1. Aluminum has atomic number 13, helium has atomic number 2, andsilicon has atomic number 14. Lithium has 3 electrons and the 3rd one occupies the l -shell. Name: Helium Symbol: He Atomic Number: 2 Atomic Mass: 4. It is the thirteenth and third-last element in the lanthanide series. Thus, hydrogen has an atomic number of 1, while iron has an atomic number of 26. deviation for a number of spectral lines of known wavelength. Properties. The nucleus of the helium atom contains 2 massive, positively charged particles.