The trend towards smaller atomic radii as one moves to the right in a period is . A) faulty, as atomic radii in a period are nearly uniform in size. B) because of electron pair repulsion causing the expansion of the orbitals. C) wrong. Atomic radii increase across a period left to right as the larger d and p orbitals are occupied after the s orbital. D) due to the effective nuclear charge decreasing. E) due to the effective nuclear charge increasing.

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.