If the number of protons in one atom of an element Y is 20, then the number of electrons in its ion $Y^{2+}$ will be :

(a) 20

(b) 19

(c) 18

(d) 16

Q. An element has atomic number $29$. It belongs to the period $x$ and group $y$. The value of $(2x+y)$ will be:

Q. The number of protons in one atom of an element X is 8. What will be the number of electrons in its ion X²⁻?
(a) 8
(b) 9
(c) 10
(d) 11

Q. The atomic number of an element X is 19. The number of electrons in its ion X⁺ will be:
(a) 18
(b) 19
(c) 20
(d) 21

Q. The atom of an element X contains 17 protons, 17 electrons and 18 neutrons whereas the atom of an element Y contains 11 protons, 11 electrons and 12 neutrons.

(a) What type of ion will be formed by an atom of element X ? Write the symbol of ion formed.
(b) What will be the number of (i) protons (ii) electrons, and (iii) neutrons, in the ion formed from X ?
(c) What type of ion will be formed by an atom of element Y ? Write the symbol of ion formed.
(d) What will be the number of (i) protons (ii) electrons, and (iii) neutrons, in the ion formed from Y ?
(e) What is the atomic mass of (i) X, and (ii) Y ?
(f) What could the elements X and Y be ?