Chem

KAP Chemistry - Ion Reference

- Ion: An atom or group of atoms that has a charge (+ or -)

- Charge: atoms develop a charge when electrons are lost or gained. Present in ionic substances.

- Oxidation number: atoms take on an oxidation number when electrons are shared unequally in covalent/molecular substances. In an ionic substance, charge = oxidation number.

- Monatomic ion: An ion made from a single atom (example: Na+, sodium ion)

- Polyatomic ion: An ion made from more than one atom (example: NO3-, nitrate ion)

Monovalent Monatomic Ions

- Monovalent: Describes ion having only one possible charge (oxidation #)

1+ 2+ 3+ 3- 2- 1- 0

1 H 2+ He

3 Li 4 Be

11 Na 12 Mg

19 K 20 Ca

37 Rb 38 Sr

55 Cs 56 Ba

87 Fr 88 Ra

Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

39 Y 40 Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I

47 48 49 50 51 52 53 54

55 Cs 56 Ba 57 La 58 Ce 59 Pr 60 Nd 61 Pm 62 Sm 63 Eu

64 Gd 65 Tb 66 Dy 67 Ho 68 Er 69 Tm 70 Yb 71 Lu

72 Hf 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au

80 Hg 81 Tl 82 Pb 83 Bi 84 Po 85 At 86 Rn

87 Fr 88 Ra 89 Ac 90 Th 91 Pa 92 U 93 Np 94 Pu

95 Am 96 Cm 97 Bk 98 Cf 99 Es 100 Fm 101 Md 102 No

103 Lr 104 Rf 105 Db 106 Sg 107 Bh 108 Hs 109 Mt

110 Ds 111 Rg 112 Cn 113 Nh 114 Fl 115 Mc 116 Lv

117 Ts 118 Og

- Elements (unshaded) in groups (columns) of the Periodic Table labeled: 1+, 2+, 3+, 3-, 2-, 1- and 0) above always* take on the charge indicated above the column when they become ions. Memorize this pattern!

- Examples: Calcium ions (Ca2+) have a 2+ charge; fluoride ions (F-) (from fluorine) have a 1- charge.

- *Exception: Hydrogen can also form a 1- ion (less common than 1+). In this case, H+ is called the hydride ion.

- Memorize these monovalent ions not in one of the above columns: Silver: Ag+ Zinc: Zn2+ Cadmium: Cd2+

Memorize Everything Above This Line