NCERT Exemplar VII — task. Science CBSE, Class 9.

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a. Rutherford’s alpha-particle scattering experiment led 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

Answer variants:

$2,8,4$

$2,8,5$

mass number

$2,8,7$

atomic number

neutrons

$2,8,6$

nucleus

protons

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36. NCERT Exemplar VII