Unit 8 - The Periodic Table

Arranged by atomic number

118 - 94 occur naturally

The columns of the periodic table

The rows of the periodic table

8

Nucleon number and proton number

• Large atomic radius • Conduct heat and electricity • Have a range of melting point values • Malleable and ductile • Shiny

• Smaller atomic radius • Do not conduct heat or electricity • Generally low melting point values • Brittle • Dull

Elements that display properties of both metals and non-metals - found in the middle of the periodic table

All elements in the same group have the same number of electrons in their outer shell

Elements with the same number of outer shell electrons react similarly

The period number shows how many shells an element has

The group number shows how many electrons are on the outer shell of the elements

Metal atoms lose electrons and form positively charged ions

Non-metal atoms gain electrons to form negatively charged ions

• Group 1 = 1+ • Group 2 = 2+ • Group 3 = 3+ • Group 4 = N/A • Group 5 = 3- • Group 6 = 2- • Group 7 = 1- • Group 8 = 0

Measure of how large individual atoms are

• Increases as you go down a group • Decreases as you go across a period

The alkali metals

Lithium, Sodium, Potassium, Rubidium, Caesium, Francium

• Reactivity increases down the group • Density increases down the group • Melting point decreases down the group • Reacts more vigorously with water down the group

• Happens on the surface of the water • Hydrogen gas given off • Effervescence can be seen • Lithium moves around on the surface • Water will become alkaline

• Lithium + Water –> Lithium hydroxide + Hydrogen • 2Na(s) + 2H2O(l) –> 2NaOH(aq) + H2(g)

• Reaction is more vigorous than Lithium • Heat given off • Metal moves on the surface of the water faster