Transcript Trends in the Periodic Table 8

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