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

Let's solve the question step by step:

### Step 1: Rutherford's Alpha-Particle Scattering Experiment
- **Statement**: Rutherford's alpha-particle scattering experiment led to the discovery of the **nucleus**.
- **Explanation**: The experiment showed that atoms have a small, dense, positively charged center called the nucleus.

### Step 2: Understanding Isotopes
- **Statement**: Isotopes have the same **atomic number** but different **mass numbers**.
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