In other words, a helium atom’s electron cloud is about 100,000 times bigger than its nucleus.Įlectrons orbiting around the nucleus of an atom are arranged in shells - also known as “energy levels.” The first shell can hold only two electrons, while the next shell holds up to eight electrons. The darker the shade, the more likely that an electron will be there. The dot in the middle is the nucleus, and the surrounding cloud represents where the two electrons might be at any time. Its atomic number is 92 and its atomic mass is 238 (92 + 146). The most common isotope of uranium has 92 protons and 146 neutrons. Its atomic number is 14 and its atomic mass is 28. For example, silicon has 14 protons and 14 neutrons. For most of the remaining elements, there are more neutrons than protons, because extra neutrons are needed to keep the nucleus together by overcoming the mutual repulsion of the increasing numbers of protons concentrated in a very small space. For helium, it is 4: two protons and two neutrons.įor most of the 16 lightest elements (up to oxygen) the number of neutrons is equal to the number of protons.
For hydrogen, the atomic mass is 1 because there is one proton and no neutrons.
HELIUM ATOMIC MASS PLUS
The number of protons is the atomic number, and the number of protons plus neutrons is the atomic mass. The positively charged protons tend to repel each other, and the neutrons help to hold the nucleus together. All other elements have neutrons as well as protons in their nucleus, such as helium, which is depicted in Figure 2.2. The proton forms the nucleus, while the electron orbits around it. The element hydrogen has the simplest atoms, each with just one proton and one electron. Table 2.1 Charges and masses of the particles within atoms Elementary Particle Both protons and neutrons have a mass of 1, while electrons have almost no mass. The negative charge of one electron balances the positive charge of one proton. As summarized in Table 2.1, protons are positively charged, neutrons are uncharged and electrons are negatively charged. The electronic configuration of Helium will be 1s2.2.1 Electrons, Protons, Neutrons, and AtomsĪll matter, including mineral crystals, is made up of atoms, and all atoms are made up of three main particles: protons, neutrons, and electrons. How do you write the electron configuration for Helium? The electronic configuration of Helium will be 1s2. What is the electronic configuration of Helium 2? What is the boiling Point of Helium in Kelvin?īoiling Point of Helium in Kelvin is 4.22 K. Melting Point of Helium in Kelvin is 0 K. What is the melting Point of Helium in Kelvin? What is the boiling Point of Helium?īoiling Point of Helium is 4.22 K. Helium has 2 electrons out of which 0 valence electrons are present in the 1s2 outer orbitals of atom. How many valence electrons does a Helium atom have? Lockyer in year 1868 in Sweden and United Kingdom. It is located in group 18 and period 1 in the modern periodic table. Helium is the 2 element on the periodic table. Helium is a chemical element with the symbol He and atomic number 2. What is the position of Helium in the Periodic Table? Helium is a chemical element with symbol He and atomic number 2. To form abbreviated notation of electronic configuration, the completely filled subshells are replaced by the noble gas of the preceding period in square brackets. The abbreviated electronic configuration of Helium is 1s2. What is the abbreviated electronic configuration of Helium? The electronic configuration of Helium is 1s2. What is the electronic configuration of Helium?
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