Question

For chlorine, Z = 17, A = 35. Give the number of protons, electrons and neutrons in

(i) chlorine atom (ii) chloride ion.

In chlorine atom (Cl),

Number of protons (Z) = 17

Number of neutrons = A — Z = 35 — 17 = 18

Answer 1

(i) In chlorine atom ($\mathrm{Cl}$):

Number of protons (Z) = 17 (Atomic number)

Number of electrons = 17.

Number of neutrons = A-Z = 35-17 = 18

(ii) In chloride ion (${\mathrm{Cl}}^{-}$):

Number of protons (Z = 17) (Atomic number)

Number of electrons = (Z+I) = 17+1 = 18 (Formed by gaining one electrons)

Number of neutrons = A-Z = 35-17 = 18