Question

(b) the grid below represents part of the periodic table. study it and answer the questions that follow.
(the letters are not the actual symbols of the elements)
(i) select the element in period three which has the shortest atomic radius. give a reason for your answer.
(ii) how does the electronegativity of p, q, and r vary? explain.
(iii) compare the atomic radius of x and y. explain.

Explanation:

• (i) In period 3, as we move from left to right, the number of protons increases while the number of electron shells remains the same. This leads to a greater effective nuclear charge, which pulls the electrons closer to the nucleus. Among the elements in period 3 (assuming the grid follows the general periodic table trends), the element with the highest atomic number (right - most in the period) will have the shortest atomic radius.
• (ii) Electronegativity is the ability of an atom to attract a shared pair of electrons in a chemical bond. As we move down a group (from P to Q to R), the atomic radius increases. The outermost electrons are further from the nucleus, and the shielding effect of inner electrons increases. So, the ability to attract electrons (electronegativity) decreases.
• (iii) X and Y are in the same period. As we move from left to right in a period, the atomic radius decreases. X is to the left of Y. So, X has a larger atomic radius than Y because as we move from left to right in a period, the number of protons increases (greater effective nuclear charge), pulling the electrons closer to the nucleus.

Answer:

• (i) The element with the shortest atomic radius in period 3 is the right - most element (assuming the grid follows the periodic table trend). Reason: As we move from left to right in a period, the number of protons increases (same number of electron shells), increasing the effective nuclear charge which pulls electrons closer to the nucleus.
• (ii) Electronegativity: \(P>Q > R\). Explanation: As we move down a group (from P to Q to R), atomic radius increases and shielding effect increases, so the ability to attract electrons (electronegativity) decreases.
• (iii) Atomic radius: \(X>Y\). Explanation: X and Y are in the same period. As we move from left to right in a period, the number of protons increases (greater effective nuclear charge), pulling electrons closer to the nucleus, so atomic radius decreases.