Which has higher atomic radius?
Li or B
Li
C or F?
F (fulfills octet)
K or Br?
Br
Li or K
K
Li or N?
P or Cl?
Cl
K+ or Na+2
K+
DAILY DOUBLE!
K or O
O
Li or K?
Li
Br- or Cl-
Br-
P or N?
N
DAILY DOUBLE!
Cl or Ar?
Ar (a noble gas won't easily give up its octet)
Explain the trends of increasing atomic radius.
Downwards increase is due to distance from nucleus, more orbital layers (n=2,3,4,etc.) are being added. Right to left because, within a period, protons are added to the nucleus as electrons are being added to the same principal energy level. These electrons are gradually pulled closer to the nucleus because of its increased positive charge.
Explain the trends of increasing electron affinity.
Upward because nucleus has more attraction to less shielded atoms, making an octet more important. Left to right because the elements in group 7A and 8A, especially, highly desire more electrons for an octet. On the other hand, atoms in group 1A or 2A, especially, highly resist adding of another electron.
Explain the trends of increasing ionization potential.
The general trend is for ionization energy to increase moving from left to right across an element period. Moving left to right across a period, atomic radius decreases, so electrons are more attracted to the (closer) nucleus. This makes it more difficult to remove an electron. Upwards because distance to nucleus decreases, increasing attractions to electrons.