Ch-6 sec-3

Atomic Size Atomic Size is measured as half the distance between two nuclei Size generally decreases with atomic number within a period Size generally increases with atomic atomic number within a group.

Atomic Size

Atomic size

Ionization Energy The energy required to remove an electron from an atom. 1 st, 2 nd, 3 rd …ionization energys 1 st ionization energy generally decreases from top to bottom within a group 1 st ionization energy generally increases from left to right within a period

Ionization Energy

Main Group Ionization Energy

Ionization Energy

Ion size Cations = positive ions resulting from loss of an electron Anions = negative ions resulting from gain of electrons Group trend: increases down a group Periodic trend: varies (general decrease )

Ionic Size

Electronegativity The ability for an atom to attract electrons when the atom is in a compound Rated on a scale of 0-4 Values decrease from top to bottom in a group Values increase from left to right within a period

Trends in Electronegativity

electronegativity

Electron Affinity The energy change that occurs when an electron is acquired by a neutral atom Most atoms release energy Periodic trend: generally increase from left to right Group trend: somewhat irregular, slightly decreases from top to bottom

Electron Affinity

Other Trends Nuclear charge: increase of protons Increases across and down Helps to explain other trends Shielding Increases down Constant across

summations

Summations

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