Unit 1: Atoms, Elements, & Compounds

Section 2.2: The Periodic Table and Chemical Properties

The Periodic TableThe periodic

table is a chart that organizes the elements according to their physical and chemical properties.

Elements of the Periodic TableAlthough there are many versions of the

periodic table, most contain the following properties:

22TiTitanium47.9

Atomic numberSymbol

Name

Atomic mass

Periodic Table Properties – Atomic NumberAtomic Number

The number of protons in the nucleus.The number of electrons surrounding the

nucleus. The number of protons equals the number of electrons giving the

atom a neutral charge.

Atomic numbers increase one by one through the periodic table.

Q: The atomic number of calcium (Ca) is 20. What can you now say about a calcium atom?

Periodic Table Properties:Atomic Mass & Mass NumberAtomic Mass

The average mass of the atoms of an element. Written as a decimal number and is measured in

amu.

Mass NumberThe number of protons and neutrons in an

atom of an element. It can be approximated by rounding off the atomic

mass. # of Neutrons = Mass Number – Atomic Number

Q: How many protons, electrons, and neutrons does an atom of Titanium contain?

Practice Question – Complete the following chart by referring to the periodic table:

Element

Name

Symbol Atomic #

Mass # # protons

# neutro

ns

# electron

s

K 19 39

18 22

Ra 226

61 47

201 80

hydrogen

Organization of the Periodic TableGroups of Elements (p.51)

All elements in the periodic table can be classified as either metals, n0n-metals, or metalloids.

Organization of the Periodic Table Groups of Elements (p.51)What are 3 physical properties of metals,

non-metals, and metalloids?

Metals Non-metals Metalloids

Organization of the Periodic Table Periods (p.52)The periodic table is divided into horizontal

rows called periods.

Periods:Horizontal rowsNumbered 1 to 7

Q: What period is Nickel located? _____Q: How many elements are in period 1?

_____

Organization of the Periodic Table Chemical FamilyThe periodic table is also divided into vertical

columns called chemical families.Chemical Family

Elements have similar physical and chemical properties.

Numbered 1 to 18.There are 4

well-known chemical families: Alkali metals alkaline earth metals halogens noble gases

Organization of the Periodic Table Chemical Family – Alkali Metals

Alkali Metals (Column 1)Li, Na, K, Rb, Cs, FrHighly reactive

The reactivity increases as you go down the group.

Are soft and can be cut with a knife.

Organization of the Periodic Table Chemical Family – Alkaline Earth Metals

Alkaline Earth Metals (Column 2)Be, Mg, Ca, Sr, Ba, RaFairly Reactive – will burn in air if heated

Are often used in fireworks since they produce bright flames

Magnesium (Mg) reacting to flame

Strontium (Sr) - red fireworks

Organization of the Periodic Table Chemical Family – Halogens

Halogens (Column 17)F, Cl, Br, I, AtNon-metalsHighly reactive

Fluorine is the most reactive while Iodine is the least.

Astatine is very rare (not much is known)

Organization of the Periodic Table Chemical Family – Noble Gases

Noble Gases (Column 18)He, Ne, Ar, Kr, Xe, RnThe most stable and unreactive elementsAt room temperature, they are colourless,

odourless gases.

Neon – glows in different colours

Neon and Argon – used in light fixtures

Organization of the Periodic Table Transition Metals

Transition MetalsMetalsFound in the center of the periodic table.These are NOT a chemical family since they are

spread over many columns.They are grouped together because of the

arrangement of their electrons (more on this later in the chapter…)

Share many common physical properties (eg., malleable, ductile, conductive, etc.)

Q: Do you know which 3 transition metals are magnetic?

Section 2.2To review and test your knowledge of the

periodic table, we will:Play Periodic Bingo!Complete some questions!!

Note: You will be having a TEST on all the material in Unit 1 up to this point. That is, Ch 1 (Sections 1.1 to 1.3) and Ch2 (Sections 2.1 and 2.2)