Study of trends in the Periodic Table - Unit 2

Question 1

Where are the alkali metals located on the Periodic Table?

Answer 1

Alkali metals make up the first column of the Periodic Table (Group IA).

Question 2

What is the valence shell configuration of all alkali metals?

Answer 2

All alkali metals have an s1 valence shell configuration.

Question 3

Where are the alkaline earth metals located on the Periodic Table?

Answer 3

Alkaline earth metals make up the second column of the Periodic Table (Group IIA).

Question 4

What is the valence shell configuration of all alkaline earth metals?

Answer 4

All alkaline earth metals have an s2 valence shell configuration.

Question 5

Where are the halogens located on the Periodic Table?

Answer 5

The halogens make up the fifth column of the p block (Group VIIA).

Question 6

What is the valence shell configuration of all halogens?

Answer 6

All halogens have an s2p5 valence shell configuration.

Question 7

Where are the noble gases located on the Periodic Table?

Answer 7

The noble gases make up the sixth column of the p block (Group VIIIA).

Question 8

What is the valence shell configuration of all noble gases?
What oxidation state do they ionize to?

Answer 8

All noble gases have an s2p6 valence shell configuration.
Trick question! Since they already have a completely filled octet, noble gases do not ionize, and they typically exist in the 0 oxidation state as free particles.

Question 9

Where are the transition metals located on the Periodic Table?

Answer 9

The transition metals make up the entire d block.

Question 10

Why do transition metals have high conductivity?

Answer 10

Transition metals have high conductivity due to their unfilled d subshells.

d electrons, by their nature, are loosely bound to the atom. As such, elements with partially-filled d subshells can be thought of as nuclei floating in a sea of unattached electrons, prime conditions for electrical conductivity.

Question 11

Describe the properties of metals in terms of their:

position in the periodic table
electronegativity
preferred oxidation state

Answer 11

Metals are generally:

found in the lower-left areas of the periodic table.
low in electronegativity, losing electron density when bonded to nonmetals.
found in positive oxidation states when in compounds.

Question 12

What are the main physical properties of metals?

Answer 12

Metals generally are/have:

good conductors of heat and electricity.
malleable, ductile, lustrous, and dense solids at room temp.
fairly high melting and boiling points.

Question 13

Describe the properties of nonmetals in terms of:

position in the periodic table
electronegativity
preferred oxidation state

Answer 13

Nonmetals are generally:

found in the upper-right areas of the periodic table.
high in electronegativity, gaining electron density when bonded to metals.
found in negative oxidation states when in compounds.

Question 14

What are the main physical properties of nonmetals?

Answer 14

Nonmetals are/have:

poor conductors of heat and electricity.
dull and brittle if they form solids at room temperature.
significantly lower melting and boiling points than metals (carbon is the primary exception).

Question 15

Describe the general trend of ionization energy heading across a row of the Periodic Table.

Answer 15

Ionization energy increases from left to right across a row of the Periodic Table.

Other notes about ionization energy:
Atoms with fully-filled subshell will have high ionization energies.
Atoms with half-filled subshells will have higher ionization energies than their neighbors.
The alkali and alkaline earth metals have very low ionization energies.

Question 16

Describe the general trend of ionization energy heading down a column of the Periodic Table.

Answer 16

Ionization energy decreases heading down a column of the Periodic Table.

The further down a column an element lies, the easier to remove. These atoms have higher n values for their valence electrons. Higher n electrons sit further from the atomic nucleus, and are therefore less strongly bound to the nucleus.

Question 17

How does atomic radius vary as atomic shell increases down a column of the Periodic Table?

Answer 17

Atomic radius increases down a column of the Periodic Table.
Each increasing shell can be thought of as another “layer” of electrons, outside the previous layer, increasing the atom’s size.
Note: The highlighted elements represent one column of the Periodic Table.

Question 18

How does atomic radius vary as atomic number increases across a row of the Periodic Table?

Answer 18

Atomic radius decreases across a row from left to right on the Periodic Table.

This is due to effective nuclear charge. As Zeff increases, the nucleus binds the electrons more tightly, pulling them in closer.
Note: the highlighted elements represent one full row of the Periodic Table.

Question 19

Define Electron Affinity

Answer 19

Electron affinity is the energy released when one valence electron is added to an atom in the gas phase.

Question 20

Describe the general trend of electron affinity heading across a row of the Periodic Table.

Answer 20

Electron affinity increases from left to right across a row of the Periodic Table.
The smaller an atom is, the closer a newly-added valence electron gets to the positively-charged nucleus, and the more energy released when that electron is added.

Question 21

Describe the general trend of electron affinity heading down a column of the Periodic Table.

Answer 21

Electron affinity decreases heading down a column of the Periodic Table.
The further down a column an element lies, the higher the value of n for its valence electrons. Higher n electrons sit further from the atomic nucleus, and so are less bound to the nucleus and release less energy when added.

Question 22

Define Electronegativity

Answer 22

An atom’s electronegativity describes that atom’s tendency to attract electron density towards itself through a chemical bond.

Note: electronegativity only applies to atoms in a bond. There is no such concept as the electronegativity of a bare atomic species.

Question 23

Describe the general trend of electronegativity heading across a row of the Periodic Table.

Answer 23

Electronegativity increases from left to right across a row of the Periodic Table.
The smaller an atom is, the closer the electrons in its bonds get to the positively-charged nucleus, and the more strongly the electrons are attracted to the nucleus.

Question 24

Describe the general trend of electronegativity heading down a column of the Periodic Table.

Answer 24

Electronegativity decreases heading down a column of the Periodic Table.
The further down a column an element lies, the larger its radius. This puts more space between the positively-charged nucleus and the electrons in any bonds it makes, reducing the attraction between the nucleus and the electrons.

Question 25

Which element has the highest electronegativity?

Answer 25

Fluorine

Electronegativity increases the further right and the closer to the top of the Periodic Table an element is. Fluorine, which is the top-right element that isn’t a noble gas, therefore has the highest value of electronegativity.

On the Pauling scale, the most commonly-used scale for determining electronegativity values, fluorine has the highest value possible: 4.0.

Question 26

What class of elements have the highest values of electronegativity?

Answer 26

Nonmetals are the most electronegative elements.

Fluorine is the element with the highest electronegativity, and as a general rule, the closer an element is to fluorine, the higher its electronegativity.

Some other notes about electronegativity:
The halogens are the most electronegative group.
Noble gases capable of making bonds (Xe and Kr) are relatively strongly electronegative.

Metals, particularly the alkali and alkali earth metals, are generally electropositive (very low electronegativity).

Question 27

What are the laws of Electrostatic Force

Answer 27

Opposite Charges Attract. (+ and -)