Periodic Table Mysteries Unraveled! Periodic trends Ch 5

Periodic LAW  When elements are arranged in order of increasing atomic number, there is a periodic repetition of the physical and chemical properties.

Organization of Periodic table  Metals  Luster and shine  Good conductor of electricity and heat  Malleable  Nonmetals  Many are gasses at room temperature  No luster or shine, bad conductors of electricity and heat.  Semimetals Metalloids  These have properties of both

Valence electrons  Group 1A:  H: 1s 1  Li: 1s 2 2s 1  Na: 1s 2 2s 2 2p 6 3s 1

Size

Atomic Radii  Distance from the center of the atom’s nucleus to it’s outer most electron.  Take the diameter divided in half.  OR the ½ the distance between the two nuclei.

Ionization Energy What is an Ion? Cation vs anion

Ionization Energy  Energy needed to remove the first electron from an atom.  Group Trends:  Ionization energy decreases as atomic number increases.  Period Trends:  Ionization energy increases from left to right  The larger the atom the easier it is to take an electron from the atom.

Electronegativity  The ability of an atom to attract electrons in a compound.  NOBLE GASSES DO NOT COUNT!  Electronegativity increases from left to right  Electronegativity decreases from top to bottom.

Electron Affinity  The energy change that occurs when it gains an extra electron.  Can have positive and negative electron affinity –Some elements release energy when they get an electron.  Ne (g) + e -  Ne - (g)29 kJ/mol  F (g) + e -  F - (g) -328 kJ/mol

TRENDS

Write a Summary: Describe the trends that are on the periodic table. Describe the trends in relation to one another as well.