TOPIC: Metals vs Nonmetals

Classifying the Elements
• 2/3 (75%) of elements are metals
• Remaining elements: non-metals & metalloids
(semi-metals)
• Metalloids:
– some properties of metals & some properties of nonmetals
• Staircase:
– dividing line between metals & nonmetals
– elements to left are metals (except H)
– elements to right are non-metals

Most elements are solid at room temperature
• Some nonmetals are gases
– All the noble gases, of course
– Some diatomics (H
2
N
2
O
2
F
2
Cl
2
)
• There are only 2 Liquids at STP (room temp)
– Br
2
(non-metal) and Hg (metal)

Properties of Metals
• Malleable – flattened into sheets
• Ductile – drawn into wires & tubes
• have Luster
• Good Conductors of heat & electricity
• Solid at room temperature (except Hg)
• Metals lose electrons & form positive ions
“ Metals are losers ”
• Most reactive metal is Fr
• Most reactive family is Alkali Metals

So…metals don’t want electrons, they want to get rid of them

Metals also have…
• Low electronegativity (low attraction for electrons)
• Low ionization energy (doesn’t take a lot of energy to remove an electron)

Decreased Electronegativity
Decreased Ionization energy

Properties of Nonmetals
• generally gases or solids (except Br
2
)
• solids are Brittle
• solids are Dull
• poor conductors of heat & electricity
• Nonmetals gain electrons & form negative ions
“ Nonmetals are winners ”
• Most reactive nonmetal is F
– Properties: OPPOSITE of metals

So…nonmetals love electrons, they want to take electrons

Nonmetals also have…
• high electronegativity (high attraction for electrons)
• high ionization energy (takes a lot of energy to remove an electron)

Increased Electronegativity
Increased Ionization energy

Properties of Metalloids
7 metalloids:
– 5 on right of staircase: B,Si,As,Te,At
– 2 on left of staircase: Ge,Sb
Each metalloid has some metallic and some nonmetallic properties
• shiny like metal but brittle like nonmetal
(except Al) and have some properties of metals and some of nonmetals

Cs has more energy levels, so it’s bigger previous | index | next
Li: Group 1 Period 2 Cs: Group 1 Period 6

Atomic Radius
Gets Bigger

previous | index | next
How about as you go across?!

previous | index | next as go across row size tends to decrease a bit because of greater PPP “ proton pulling power ”

Atomic Radius Gets Smaller