Which of the following set of elements is written correctly in the order of their increasing metallic character?

Which one of the following does not increase while moving down the group of the periodic table?

On moving from left to right in a period of the periodic table, the atomic number of elements increases. What happens to the size of atoms of elements on moving from left to right in a period?

The atomic numbers of the three elements X, Y and Z are 2, 6 and 10 respectively.

(i) Which two elements belong to the same group?

(ii) Which two elements belongs to the same period?

Give reasons for your choice.

An atom has the electron structure of 2, 7.

(a) What is the atomic number of this atoms?

(b) To which of the following would it be chemically similar?

₇N, ₁₅P, ₁₇Cl, ₁₈Ar

(c) Why would you expect it to be similar?