Arrange the following atoms according to decreasing effective nuclear charge experienced by their valence electrons: Cl, Na, P, and S. Rank from largest to smallest. To rank items as equivalent, overlap them. Cl Na P S
Largest Smallest

Cl < S < P < Na

Explanation:

We have to understand the trend for effective nuclear charge before answering the question;

The periodic table tendency for effective nuclear charge: Increase across a period (due to increasing nuclear charge with no accompanying increase in shielding effect). Decrease down a group (although nuclear charge increases down a group, shielding effect more than counters its effect).

Based on this, the elements can be arranged in the following order;

In decreasing order;

Cl < S < P < Na

what are the choices?

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.