Question

Put tick (✓) against correct choice and cross (x) against
wrong choice in questions 15, 16 and 17

15. Rutherford's alpha-particle scattering experiment was
responsible for the discovery of
(a) Atomic Nucleus (b) Electron
(c) Proton
(d) Neutron

16. Isotopes of an element have
(a) the same physical properties
(b) different chemical properties
(c) different number of neutrons
(d) different atomic numbers.

17. Number of valence electrons in Cl- ion are:
(a) 16 (b) 8 (c) 17 (d) 18​

Answer 1

Answer:

15. Atomic nucleus

16. different number of neutrons

17. 8

Explanation:

15. Rutherford discovered that some alfa particles returned back leads to the discovery of atomic nucleus.

16. Isotopes have same no. of protons leading to same atomic number but different no. of neutrons leading to different atomic weight.

17. Cl- means Chlorine gained one electron hence -1 charge on 8t, leades to 8 valence electrons in its outermost shell. (Cl has 7 electrons in outermost shell.)

Answer 2

15 Answer is (A)

16 = Answer is (C)

17 = Answer is (C)