7th Grade Ch 3 Sec 4 Nonmetals & Metalloids

Ch. 3 Ch. 3 Sec. 4 Sec. 4

Nonmetals & Nonmetals & MetalloidsMetalloids

NonmetalNonmetal•Element that lacks most properties of metals–dull- not shiny–brittle- not malleable–poor conductors

NonmetalsNonmetals•Located at right of zigzag line on periodic table

•10/16 = gases•Most form compounds, except Group 18

The table salt on a pretzel is mined from deposits

found on Earth. The same

compound can also be formed from a reaction

between the metal sodium and the

nonmetal chlorine.

Boron FamilyBoron Family

•Group 13

Carbon FamilyCarbon Family• Group 14• C (nonmetal) Pb• 4 valence electrons

Carbon FamilyCarbon Family•Contains elements

important to life & computers

•Carbon = basis for an entire branch of chemistry

•silicon & germanium- important semiconductors

Nitrogen FamilyNitrogen Family• Group 15• N Bi• 2 nonmetals- N & P• 5 valence electrons

Nitrogen Nitrogen FamilyFamily

• Group 15• Nitrogen makes up

over ¾ of the atmosphere.

• Nitrogen and phosphorus are both important in living things.

• Most of the world’s nitrogen is not available to living things.

• The red stuff on the tip of matches is phosphorus.

Diatomic Diatomic moleculesmolecules

•Compounds of 2 identical

atoms

Oxygen FamilyOxygen Family• Group 16• O Po• 3 nonmetals- O, S, Se• 6 valence electrons

Halogen FamilyHalogen Family• Group 17• F At• 7 valence electrons• very reactive• typically gains or shares 1 electron

HalogensHalogens• Group 17• Very reactive,

volatile, diatomic, nonmetals

• Always found combined with other element in nature

• Used as disinfectants & to strengthen teeth

Noble GasesNoble Gases• group 18• He Rn• 8 valence electrons• very stable & unreactive• do not form compounds b/c do not gain,

lose, or share valence electrons

The Noble GasesThe Noble Gases• Group 18• VERY unreactive,

monatomic gases• Used in lighted

“neon” signs• Used in blimps to

fix the Hindenberg problem.

• Have a full valence shell.

The The Noble Noble GasesGases

HydrogenHydrogen• alone in upper corner• not grouped in a family• very diff. properties • has 1 proton & 1 electron• some have neutrons

MetalloidsMetalloids•on border between metals & nonmetals

•8 metalloids•characteristics of both metals & nonmetals

MetalloidsMetalloids•most useful property= varying ability to conduct electricity–used to make semiconductors= can conduct electricity under certain conditions

Periodic Table of ElementsPeriodic Table of Elements

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Alkali metals

Very reactive

Li

Fr

Name each family and give a description of each, include examples from each group.

Name______________________ Date________________

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