Question

Element A has 2 electrons in its M shell. Element B has
atomic number 7.
(a) Write equations to show how A and B form ions.
(b) If B is a diatomic gas, write the equation for the direct
combination of A and B to form a compound.
Please Explain the answer properly.
​

Answer 1

Answer:

Electrovalent Compounds And covalent compound

Answer 2

(a) The equations to show A and B form ions are:

     (i) A → A²⁺ + 2e⁻

     (ii) B + 3e⁻ → B³⁻

(b) The equation for the direct combination of A and B to form a compound would be: 3A + B₂ → A₃B₂

Explanation:

(a) Element A has 2 electrons in its M shell.

Element B has an atomic number equal to 7.

→ The electrons of an atom revolve around the nucleus of the atom in the energy levels also known as shells.

→ There are 4 energy levels or shells in an atom. These are K, L, M, and N.

The 'K' shell is the innermost shell while the 'N' shell is the outermost shell.

→ The electrons first occupy the 'K' shell, then the 'L' shell, then the 'M' shell, and at last the 'N' shell.

→ The maximum number of electrons in the K, L, M, and N shells are 2, 8, 18, and 32 respectively.

→ The element A has 2 electrons in its M shell which means its K and L shells are fulfilled. Therefore its electronic configuration would be 2, 8, 2.

• The element A will lose 2 electrons to form a stable ion.

                                             A → A²⁺ + 2e⁻

→ The element B has an atomic number of 7, therefore its electronic configuration would be 2, 5.

• The element B will gain 3 electrons to form a stable ion.

                                              B + 3e⁻ → B³⁻

(b) If B is a diatomic gas, then the equation for the direct combination of A and B to form a compound would be:

                                              3A + B₂ → A₃B₂

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