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)