2 Electronegativitya measure of the ability of an atom in a chemical compound to attract electronsTrendsElectronegativities tend to increase across each period.Electronegativities tend to decrease down a group.
3 ElectronegativityAmong the elements Ga, Br, Ca, which has the highest electronegativity? Explain why in terms of periodic trends.All elements in 4th period. Br has highest atomic number and is farthest to right so you would expect highest EN.
4 Electron Affinitythe energy change that occurs when an electron is acquired by a neutral atomTrendsElectron affinity increases across period because as electrons add to the same p sublevel of atoms with increasing nuclear charge, electron affinities become more negative across each period in the p block.Generally, electrons add with greater difficulty down a group. This is due to slight increase in effective nuclear charge down a group which decreases the electron affinities.
5 Ionization Energythe energy required to remove one electron from a neutral atom of an elementTrendsIonization energy of main group elements generally increases across each period. This is caused by an increasing nuclear charge.Ionization energy generally decreases down groups because electrons are farther from the nucleus and are more easily removed
6 Ionic RadiiA positive ion is a cation. The removal of an electron makes the radius smaller.A negative ion is an anion. The addition of an electron makes the radius larger.
7 Atomic Radiusone-half the distance between the nuclei of identical atoms that are bonded togetherTrendsAtomic radius decreases across a period because of the increasing positive charge of the nucleus.Atomic radius increases down a group because electrons occupy successively higher main energy levels which are located farther from the nucleus.Period—as electrons add to s and p sublevels in the same energy level, they are gradually pulled closer to the more highly charged nucleus.. Increased pull results in decrease in atomic radii
8 Atomic RadiusOf the elements Mg, Cl, Na, and P, which has the largest atomic radius? Explain your answer in terms of trends.Of the elements Ca, Be, Ba, and Sr, which has the largest atomic radius? Explain your answer in terms of trends.Of the elements Li, O, C, and F, identify one with the largest atomic radius and the one with the smallest atomic radius.Of the elements Br, At, F, I, and Cl, identify one with the largest atomic radius and the one with the smallest atomic radius.1.All elements in period 3. Na has lowest atomic number. AR decrease across a period.Ba has the highest atomic number and is farthest down the group. AR increases down a groupLargest: Li Smallest F Largest: At Smallest F