Question

1. fill in the electronegativity for the following elements. you will have down to \atomic data\ and look for electronegativity (pauling scal e. across a period (→): what is the trend for electronegativity across a period (→)? what is something unusual or unexpected? why do you think f. down a group (↓): what is the trend for electronegativity down a group (↓)?

Explanation:

• Across a period: As we move from left to right across a period in the periodic table, the electronegativity generally increases. This is because the atomic radius decreases (due to an increase in nuclear charge which pulls the electrons closer to the nucleus), and the atoms have a greater tendency to attract electrons. For the elements in part E (Ga - Kr which are in period 4), looking up their Pauling electronegativity values: Ga has an electronegativity of 1.81, Ge is 2.01, As is 2.18, Se is 2.55, Br is 2.96, and Kr (a noble gas, which is an exception as noble gases generally have very low electron - attracting tendencies in chemical bonding, but some values assign it a very low value, say close to 0 in the context of this basic trend) shows the increasing trend (ignoring Kr as a special case for the general trend among the non - noble gas elements in the period).
• Down a group: As we move down a group in the periodic table, the electronegativity generally decreases. This is because the atomic radius increases (more electron shells are added), and the outermost electrons are further from the nucleus and less strongly attracted. For the elements in part F (N - Bi which are in group 15), looking up their Pauling electronegativity values: N has an electronegativity of 3.04, P is 2.19, As is 2.18, Sb is 2.05, and Bi is 2.02, which shows a decreasing trend.

Answer:

• Across a period: Electronegativity generally increases (e.g., for Ga (1.81), Ge (2.01), As (2.18), Se (2.55), Br (2.96) in period 4, ignoring the noble gas Kr as a special case).
• Down a group: Electronegativity generally decreases (e.g., for N (3.04), P (2.19), As (2.18), Sb (2.05), Bi (2.02) in group 15).