The Periodic Table

Question 1

What is effective nuclear charge (Zeff)?

Answer 1

measure of the net positive charge from the nucleus experienced by valence electrons

Question 2

What is the pattern of Zeff in the Ptable?

Answer 2

across a period, Zeff increases from left to right

down a group, little change

Question 3

what is atomic radius?

Answer 3

one half the distance between the center of two atoms (can’t measure by examining one atom)

Question 4

what is the pattern of atomic radius in Ptable?

Answer 4

across a period, decreases from left to right

down a group, increases from top to bottom

Question 5

what is ionic radius?

Answer 5

the size of a charged species

Question 6

are cations and anions smaller or larger than their corresponding neutral atoms?

Answer 6

cations - smaller

anions - larger

Question 7

what is ionization energy?

Answer 7

energy required to remove a valence electron from a gaseous species

Question 8

what is the pattern of ionization energy in Ptable?

Answer 8

across period, increases from left to right

down a group, decreases from top to bottom

Question 9

what is electron affinity?

Answer 9

energy released upon the addition of an electron to the valence shell of a gaseous species

Question 10

what is the pattern of electron affinity?

Answer 10

(follows that of Zeff)
across a period, increases from left to right
down a group, decreases from top to bottom

Question 11

what is electronegativity?

Answer 11

measure of attractive force of the nucleus on electrons within a bond

Question 12

what is the pattern of electronegativity in Ptable?

Answer 12

across a period, increases from left to right

down a group, decreases from top to bottom

Question 13

what are chalcogens?

Answer 13

Group 16 elements
oxidation states ranging from +2 to -6
biologically important

Question 14

what are characteristics of metals?

Answer 14

lustrous (shiny), conductors, malleable (hammered into shapes), ductile (pulled into wires)

Question 15

what are characteristics of nonmetals?

Answer 15

dull, poor conductors, brittle

Question 16

What are the three factors that affect basicity of amount and acidity (ie. stabilization of a conjugate base)?

Answer 16

1. electronegativity: across a period, more electronegative, more stable with the (-) charge on it, stronger acid/weaker base
2. size: down a group, larger size, more charge dispersion, more stable with the (-) charge on it,
   stronger acid/weaker base
3. resonance: more resonance, more stable with the (-) charge on it, stronger acid/weaker base