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........ .