Trends in the Periodic Table Trends in Mass

Trends in the Periodic Table

Trends in Mass • As you move from left to right across a period, mass increases • As you move from top to bottom down a group, mass increases • Masses get larger in both these cases as the atoms have more protons, neutrons and electrons

Trends in Atomic Radius • As you move from left to right across a period atomic radius DECREASES!! – This is because the electrons are “pulled in” closer to the nucleus as the number of protons increases…. the atom “shrinks” in a bit. – See graph on p. 23

Trends in Atomic Radius • As you move from top to bottom down a group, atomic radius INCREASES as the atoms have more electron shells.

Trends in Reactivity for Metals • As you move from left to right across a period, reactivity decreases for metals • As you move from top to bottom down a group, reactivity increases for metals The most reactive metal is francium (Fr)

Trends in Reactivity for Nonmetals • As you move from left to right across a period, reactivity for non-metals increases • As you move from top to bottom down a group, reactivity for non-metals decreases. • Remember the noble gases are NONREACTIVE, so the most reactive nonmetal is fluorine (F)

Trends in Ionization Energy • Ionization energy is the energy required to remove the outermost electron from an atom • Ionization energy increases across a period and decreases down a group

Trends in Ionization Energy