L1 /
10
CH1012
RADII AND IE1-
GROUPS
• the atomic
and ionic radii within each group increase down the group because of the greater number of electron shells that accompany the increase in atomic number.
Zeff (effective nuclear charge) remains essentially constant on descending a group.
Zeff (effective nuclear charge) remains essentially constant on descending a group.
• Ionisation
energies (IE1): M(g) ® M+(g) + e-decrease going down
the group, the atoms get larger
& so the outermost electrons are further from the attractive nuclear charge.
meaning it takes less energy to eject them.
meaning it takes less energy to eject them.
• (N.B. for
Groups 3 & 4 the lowest element in the group has a slightly higher IE1 than the previous one due to lanthanide contraction)