Parveen Singh

For electronic configuration, we only need to consider the electrons, which are not affected by the number of neutrons (isotopes) or the same mass number (isobars).

Subatomic Particles in H, D, and T

Symbol Protons Neutrons Electrons
H 1 0 1
D (Deuterium) 1 1 1
T (Tritium) 1 2 1

Oxygen (O) has an atomic number of 8 and usually has 8 neutrons in its nucleus, so its most common isotope has a mass number of 16 (8 protons + 8 neutrons).
Sulphur (S) has an atomic number of 16. Its most common isotope has 16 neutrons, giving it a mass number of 32 (16 protons + 16 neutrons).

If the number of electrons in an atom is 8 and the number of protons is also 8

Valency is the number of electrons that an atom can gain or lose to attain the nearest noble gas configuration. Chlorine, sulphur and magnesium are all elements in the periodic table. The valency of an element can be determined by looking at its electronic configuration.

If the K and L shells of an atom are full, it means that the first and second electron shells are filled. According to the electronic configuration rules, the maximum number of electrons in the K shell (first shell) is 2, and the maximum number of electrons in the L shell (second shell) is 8. Therefore, the total number of electrons in the atom would be 2 (from the K shell) + 8 (from the L shell) = 10 electrons.

Carbon (Atomic number 6): Electron distribution – 2 electrons in the first shell (K shell) and 4 electrons in the second shell (L shell). Or 2, 4
Sodium (Atomic number 11): Electron distribution – 2 electrons in the first shell (K shell), 8 electrons in the second shell (L shell), and 1 electron in the third shell (M shell). Or 2, 8, 1

To find the number of neutrons in a helium atom, you subtract the number of protons from the atomic mass.

Helium atomic mass = 4 u

Number of protons = 2

Number of neutrons = Atomic mass – Number of protons = 4 – 2 = 2

Therefore, helium atom has 2 neutrons.

Protons: Positively charged particles located in the nucleus. Neutrons: Neutral particles located in the nucleus. Electrons: Negatively charged particles that orbit the nucleus.

If an alpha-particle scattering experiment is carried out using a metal foil other than gold, there would be no change in observations if the foil is as thin as the gold foil used by Rutherford. This is because the basic structure of an atom remains the same regardless of the material. However, other metals are

Draw a sketch of Bohr’s model of an atom with three shells. K SHELL, L SHELL, M SHELL,

He projected alpha particles (helium nuclei) at gold foil, and the positive alpha particles were deflected. This led Rutherford to conclude that protons exist in a nucleus and have a positive nuclear charge