Question

Q-3) TRUE OR FALSE
9) Isotopes of an element have different number of neutrons.
10) Number of valence electrons in Cl ion are 8
11) The mass of an object is constant every where in the universe​

Answer 1

Answer:

1.true

2.false in cl Valence electrons are 7

3.false mass of objects are different

Answer 2

Answer:

1) Isotopes of any given element all contain the same number of protons, so they have the same atomic number (for example, the atomic number of helium is always 2). Isotopes of a given element contain different numbers of neutrons, therefore, different isotopes have different mass numbers.

2) Cl− is formed from adding one electron so the new electronic configuration is 2, 8, 8. So the valence electrons is 8.

3) No matter where you are in the universe, your mass is always the same: mass is a measure of the amount of matter which makes up an object. Weight, however, changes because it is a measure of the force between an object and body on which an object resides (whether that body is the Earth, the Moon, Mars, et cetera).