Question 1

How do you use electronegativity to determine bond type?

Accepted Answer

Subtract the smaller Pauling value from the larger and read off the rough character. ΔEN = 0 (H-H, Cl-Cl): nonpolar covalent. ΔEN ≈ 0.1-0.4 (C-H at 0.35): essentially nonpolar covalent with a small dipole. ΔEN ≈ 0.5-1.7 (H-Cl at 0.96, O-H at 1.24): polar covalent. ΔEN > 1.7 (Na-Cl at 2.23): predominantly ionic. The 1.7 cutoff is a Pauling-era heuristic — real bonds form a continuum, and HF (ΔEN = 1.78) is usually called polar covalent despite the threshold. Use ΔEN to rank, not to classify rigidly.

Question 2

Why does fluorine have the highest electronegativity?

Accepted Answer

Three factors stack in fluorine's favor. First, small atomic radius — the bonding electrons sit close to the +9 nucleus, where the Coulomb pull is strong. Second, only a 1s² core shielding the valence shell, so most of the nuclear charge reaches the bond. Third, seven valence electrons mean fluorine is one electron short of a closed shell, so completing the octet is highly favorable. Pauling assigned fluorine 3.98 as the scale anchor; nothing else outranks it in any common bonding situation. (Some computational scales give noble-gas compounds higher numbers, but those don't show up in routine bond-polarity work.)

Question 3

What are the periodic trends in electronegativity?

Accepted Answer

Across a period (left to right), nuclear charge climbs while electrons pile into the same valence shell — atomic radius shrinks slightly and the effective pull on bonding electrons increases. Down a group (top to bottom), each new period adds an inner shell that shields the valence electrons from the nucleus, and the valence shell itself sits farther out, so the pull weakens. Net result: the highest electronegativities cluster in the upper right (F at 3.98, O at 3.44), the lowest in the lower left (Cs at 0.79, Fr unmeasured but estimated near 0.7). The trend is the same skeleton as ionization energy and electron affinity.

Atomic Number	Symbol	Element	Electronegativity (Pauling)	Group	Period
1	H	Hydrogen	2.2	1	1
3	Li	Lithium	0.98	1	2
4	Be	Beryllium	1.57	2	2
5	B	Boron	2.04	13	2
6	C	Carbon	2.55	14	2
7	N	Nitrogen	3.04	15	2
8	O	Oxygen	3.44	16	2
9	F	Fluorine	3.98	17	2
11	Na	Sodium	0.93	1	3
12	Mg	Magnesium	1.31	2	3
13	Al	Aluminum	1.61	13	3
14	Si	Silicon	1.9	14	3
15	P	Phosphorus	2.19	15	3
16	S	Sulfur	2.58	16	3
17	Cl	Chlorine	3.16	17	3
19	K	Potassium	0.82	1	4
20	Ca	Calcium	1	2	4
21	Sc	Scandium	1.36	3	4
22	Ti	Titanium	1.54	4	4
23	V	Vanadium	1.63	5	4
24	Cr	Chromium	1.66	6	4
25	Mn	Manganese	1.55	7	4
26	Fe	Iron	1.83	8	4
27	Co	Cobalt	1.88	9	4
28	Ni	Nickel	1.91	10	4
29	Cu	Copper	1.9	11	4
30	Zn	Zinc	1.65	12	4
31	Ga	Gallium	1.81	13	4
32	Ge	Germanium	2.01	14	4
33	As	Arsenic	2.18	15	4
34	Se	Selenium	2.55	16	4
35	Br	Bromine	2.96	17	4
37	Rb	Rubidium	0.82	1	5
38	Sr	Strontium	0.95	2	5
42	Mo	Molybdenum	2.16	6	5
44	Ru	Ruthenium	2.2	8	5
45	Rh	Rhodium	2.28	9	5
46	Pd	Palladium	2.2	10	5
47	Ag	Silver	1.93	11	5
48	Cd	Cadmium	1.69	12	5
49	In	Indium	1.78	13	5
50	Sn	Tin	1.96	14	5
51	Sb	Antimony	2.05	15	5
52	Te	Tellurium	2.1	16	5
53	I	Iodine	2.66	17	5
55	Cs	Cesium	0.79	1	6
56	Ba	Barium	0.89	2	6
74	W	Tungsten	2.36	6	6
76	Os	Osmium	2.2	8	6
77	Ir	Iridium	2.2	9	6
78	Pt	Platinum	2.28	10	6
79	Au	Gold	2.54	11	6
80	Hg	Mercury	2	12	6
82	Pb	Lead	1.87	14	6
83	Bi	Bismuth	2.02	15	6

Electronegativity Values (Pauling Scale) for Common Elements

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