Chp. 2 The Periodic Table Flashcards
Accounts for ~10% of questions in the Chemistry section for the MCAT.
1
Q
What is the periodic law?
A
The chemical and physical properties of the elements are dependent upon their atomic numbers
2
Q
What are A elements?
A
- Representative elements
- Include groups IA-VIIIA
- Their valence e- are in either s or p orbitals
3
Q
What are B elements?
A
- Nonrepresentative elements
- Include transition elements and lanthanide and actinide series
- Their valence e- are in s and d (transition) and s and f orbitals
4
Q
Characteristics of metals
A
- Found on the left and middle of periodic table
- Include active and transitional metals and lanthanide and actinide series
- High melting points and densities
- Very malleable; ductility
- Good conductors
5
Q
Characteristics of nonmentals
A
- Found on the upper right side of the periodic table
- Brittle in solid state
- Poor conductors
- Don’t easily give up e-
6
Q
Characteristics of metalloids
A
- Electronegativities and ionization energies lie b/w *metals and nonmetals
- Physical properties (boiling point, density, etc) vary
- Reactivities depend on what they’re reacting with
7
Q
What is the effective nuclear charge (Zeff)?
A
- The electrostatic attraction between the valence e- and the nucleus. It measures a net positive charge.
- Increases L to R in a period
- Remains constant within a group
8
Q
What happens when you move down the elements of a given group?
A
- The principal quantum number increases by 1
- Valence e- separate from the nucleus more and more
- Electrostatic attraction is reduced b/w valence e- and nucleus
- Valence e- aren’t held as tightly
9
Q
What is the atomic radius?
A
- Half of the distance between the centers of two atoms of an element
- Decreases from L to R
- Increases top to bottom
- Largest atom is Cs in group 1A (1) and smallest is He
10
Q
- Half of the distance b/w the nucleus and valence e- of an ion
- Nonmetals closer to the metalloid line have a larger radius
- Metals closer to the metalloid line have a smaller radius and have fewer e- to lose
A
What is the ionic radius?
11
Q
What is ionization energy?
A
- The energy required to remove an electron from a gaseous species
- Endothermic process
- Increases L to R
- Decreases top to bottom
- Elements in the groups 1 and 2 are low in this and are called active metals
12
Q
What are the first and second ionization energies?
A
- First: the energy needed to remove the first electron; will always be smaller than the second
- Second: the energy needed to remove the second electron from the univalent cation (X+) to form the divalent cation (X2+); larger for group IIA
13
Q
- The energy given off by a gaseous species when it gains an electron
- Exothermic process
- Increases L to R
- Decreases top to bottom
- Groups 1 and 2 are low in this; group 17 is high in this *Noble gases’ value in this is 0
- Metals are low in this
A
What is electron affinity?
14
Q
- A measure of the attractive force that an atom will put on an electron in a chemical bond
- When this increases, the more electrons will be attracted within a bond
- When ionization is low/high, this is low/high
- Increases L to R
- Decreases top to bottom
A
What is electronegativity?
15
Q
What increases from left to right on the periodic table?
A
Ionization energy
E- affinity
Electronegativity
