Fill in the blanks in the following statements.
(a) Rutherford's `alpha`-particle scattering experiment lead to the discovery of the …….. .
(b) Isotopes have same……… but different……. .
(c) Neon and chlorine have atomic numbers 10 and 17 respectively. Their valencies will be...... and........ respectively.
(d) The electronic configuration of silicon is .......... and that of sulphur is........ .

Explanation

(a) nucleus.
(b) atomic number, mass number.
(c) zero, one.
`10^(Ne)` -Electronic configuration 2, 8. Its outermost shell is completely filled.
Hence, its valency is zero.
`17^(Cl)`-Electronic configuration 2, 8, 7
It can complete its outermost shell by gaining 1 electron.
Hence, its valency = 1
(d) 2, 8, 4 and 2, 8, 6.