Characteristics of Groups in the Periodic Table

Group on the Periodic Table

Elements in a group have similar chemical properties due to the same number of valence electrons.

Atomic Number

Number of protons in an atom, which determines the nuclear charge and the arrangement of the Periodic Table.

Atomic Radius

Distance between the nucleus and the farthest electron.

Atomic Radius Group Trend

Atomic Radius increases as you go down the group due to more occupied principal energy levels.

First Ionization Energy (IE)

The amount of energy needed to remove the most loosely bound electron from the valence shell.

Ionization Energy Trend

Ionization Energy decreases as you go down a group because larger radius atoms have valence electrons farther from the nucleus.

Electronegativity (EN)

A measure of the attraction of a nucleus of one atom for another atom's valence electrons.

Electronegativity Group Trend

Electronegativity decreases as you go down the group due to larger atomic radius.

Metallic Property

Measure of how easily an element loses electrons.

Metallic Property Group Trend

Metallic properties increase as you go down the group.

Example of Group 1 Compound

Na+1 Cl-1 → NaCl

Example of Group 13 Compound

B+3 O-2 → B2O3

Atomic Radius Example

Li = 130 pm, Cs = 238 pm

Group IA Ionization Energy Example

Li = 520 KJ/mol, Fr = 393 KJ/mol

Electronegativity Scale

A man-made scale from 0 to 4.

Group Review Question 1

Which of the following has the highest electronegativity; Ca or Ba? Why?

Group Review Question 2

Which of the following is most metallic; Li or Rb? Why?

Group Review Question 3

Which pair of elements have most similar characteristics; K & Cl, K & Ca, or F & Cl? Why?

Group Review Question 4

Which of the following has the lowest Ionization Energy; Ca or Ba? Why?

Diatomic Element

An element that exists as a molecule composed of two atoms.

Element with greatest metallic character in Group 15

Bismuth (Bi)

XO formation

Metal 'X' comes from Group 2.

Element in group 2 with largest electronegativity

Magnesium (Mg)

Element in group 3 with smallest ionization energy

Aluminum (Al)

Group 1

Alkali Metals - Extremely Active, Form Strong Bases.

Group 2

Alkaline Earth Metals - Very Active; but not as much as the Alkali Metals.

Properties of Groups 1 & 2

Found only in compounds in nature, are the most active metals on the Periodic Table, lose electrons easily.

Low Ionization Energy

A characteristic of elements in Groups 1 and 2.

Low Electronegativity

A characteristic of elements in Groups 1 and 2.

Ionic Compounds

Compounds formed by elements in Groups 1 and 2.

Transition Metals

Elements in Groups 3 to 12 that have multiple oxidation numbers.

Colored Ions in Water

Transition metals can form compounds which have colored ions in water.

Elemental Transition Metals

Examples include Gold (Au), Copper (Cu), and Silver (Ag).

Mercury (Hg)

The only metal that is liquid at room temperature.

Halogens

Group 17 elements that all have 7 valence electrons and gain 1 electron to become -1 ions.

Phosphorus

Not a diatomic element.

Nitrogen

A diatomic element.

High Electronegativity

Gain another atom's electrons easily

High Ionization Energy

Do not lose their electrons easily

Noble Gases

All are Non Metals & Gases at Room Temp

Noble Gases Reactivity

DO NOT react with other elements because they have filled/stable outer shell

Valence Electrons in Noble Gases

8 valence electrons = full shell, except He which has 2 valence electrons = full shell

Characteristics of a Period

Elements in the same period have the same number of occupied Principal Energy Levels (PEL's).

Period 3 Elements

All have 3 occupied rings.

Atomic Number Trend in a Period

Atomic Number Increases as one moves across a period.

Valence Electrons Trend in a Period

Number of Valence Electrons Increase as one moves across a period.

Atomic Radius Trend in a Period

Atomic Radius Decreases as one moves across a period due to greater nuclear charge.

Atomic Radius Values

Na: 190, Mg: 160, Al: 143 (in pm) showing more protons pull electrons closer to the nucleus.

Ionization Energy Trend in a Period

Ionization Energy Increases as one moves across a period, requiring more energy to remove electrons from non-metals than metals.

Electronegativity

The attraction for another atom's electrons increases.

Atomic radius

Decreases; atom's nucleus is closer to another atom's valence electrons.

Nuclear Charge

Greater nuclear charge causes electrons to be held closer to the nucleus due to a smaller radius.

Metals

Elements that lose electrons to become (+) ions; have properties like luster, ductility, malleability, and good conductivity.

Non-Metals

Elements that gain electrons to become (-) ions; most are gases, some are solids, and they lack luster and are poor conductors.

Metalloids

Elements that have some properties of both metals and non-metals; located at the staircase between metals and non-metals.

Ionic Radius

For metals, it is smaller than atomic radius; for non-metals, it is larger than atomic radius.

Most Active Metals

Found lower and to the left of the periodic table; Francium (Fr) is the most reactive metal.

Most Reactive Non-Metal

Fluorine (F) is the most reactive non-metal.

Properties of Metals

Have luster, are ductile, malleable, good conductors of electricity and heat, and are all solids at room temperature except mercury (Hg).

Properties of Non-Metals

High electronegativity (E.N.), high ionization energy (I.E.), most are gases, and Br is the only liquid non-metal.

Properties of Metalloids

Elements that are malleable and have poor conductivity; examples include B, Si, As, Te, Ge, Sb.

Ductile

Can be drawn into a wire.

Malleable

Can be hammered into shape.

Good Conductor

Ability to conduct electricity and heat effectively.

Luster

Shine or reflective quality of a surface.

Brittle

Tendency to break or shatter easily.

Liquid Non-Metal

Bromine (Br) is the only liquid non-metal.

Solid Non-Metal

Iodine (I) is a solid non-metal at room temperature.

Low Ionization Energy

Characteristic of metals, indicating they lose electrons easily.

Low Electronegativity

Characteristic of metals, indicating a weak attraction for electrons.