Isotopes and Ions Isotopes l l Atoms of

Isotopes and Ions

Isotopes l l Atoms of the same element that have different masses Have the same number of protons and electrons but different numbers of neutrons

How many protons, neutrons, & electrons are in the following? l Bromine – 80 l Write the hyphen notation for the element that contains 15 electrons and 15 neutrons l 13 C 6 l 35 p, 35 e, 45 n l Phosphorus – 30 l 6 p, 6 e, 7 n

Average Atomic Mass l l l Weighted average of the atomic masses of naturally occurring isotopes of an element This is the number that appears on the periodic table (abundance of isotope in decimal form) X (atomic mass of isotope) + (abundance of isotope in decimal form) X (atomic mass of isotope)

Example l Naturally occurring copper consists of 69. 17% copper-63, which has an atomic mass of 62. 929 599 and 30. 83% copper-65, which has an atomic mass of 64. 927 793. Find the average atomic mass of copper. l (. 6917) X (62. 929 599) + (. 3083) X (64. 927 793) = l 43. 5284 + 20. 0172 = 63. 55

Ions l An atom or group of bonded atoms that has a positive or negative charge l Positive ions have lost electrons. They have more protons than electrons. Ex: Ca 2+ l Negative ions have gained electrons. They have more electrons than protons. Ex: N 3 -

How many protons, neutrons, and electrons are in the following: l Na+ l Cl- l Mg 2+ l O 2 - l Al 3+ l 11 p, 12 n, 10 e l 17 p, 18 n, 18 e l 12 p, 12 n, 10 e l 8 p, 8 n, 10 e l 13 p, 14 n, 10 e