7. (a) The following elements represent atoms of elements showing their mass numbers and atomic numbers:

Question

40 Ar and 39 K
18 19
i. Explain why argon has lower atomic number but greater atomic mass than that of potassium.
ii. Explain why argon is neither metallic nor non-metallic element?
iii. Potassium has atomic number of 19. Give three deductions which can be made from this statement.

Answer 1

1. Ar has 18 protons and 22 neutrons; K has 19 protons and 20 neutrons.
2. Can't do it. Ar is about as non-metallic an element as you would want.
3. Deductions: Three facts are K has 19 protons. K has 19 electrons. K has no net electric charge.