How substances are named:• Depends on what they are composed of• Elements have only one name which is based

on their identity (names on the periodic table) and is represented by a unique symbol

• Some Element names are attached to another word that further describes them:

• Ex. Hydrogen gas, liquid Bromine, molecular Nitrogen, atomic Oxygen

• MEMORIZE: Diatomic elements

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About ¾ of the elements are classified as metals. They have a reflective surface, conduct heat and electricity better than other elements, and are malleable and ductile. Metals generally tend to form (+) positive ions when charged.

Most of the remaining elements are classified as nonmetals. Their solids have a non-reflective surface, do not conduct heat and electricity well, and are brittle. Nonmetals generally tend to form (-) negative ions when charged.

A few elements are classified as metalloids. Their solids have some characteristics of metals and some of nonmetals.

How ions form:

• Cations (+) positive ions have more protons than electrons. How? They have lost 1 or more electrons

• Anions (-) negative ions have more electrons than protons. How? They have picked up 1 or more electrons

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Ion Charge and the Periodic Table• The charge on an ion can often be

determined from an element’s position on the Periodic Table

• Metals always form positively charged cations

• For many main group metals, the charge = the group number

• Nonmetals form negatively charged anions• For nonmetals, the charge = the group

number − 8

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Practice – What is the charge on each of the following ions?

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• potassium cation• sulfide anion• calcium cation• bromide anion• aluminum cation

K+

S2−

Ca2+

Br−

Al3+

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Metals• Solids at room temperature, except Hg• Reflective surface

– shiny• Conduct heat• Conduct electricity• Malleable

– can be shaped• Ductile

– can be drawn or pulled into wires• Lose electrons and form cations in

reactions• About 75% of the elements are metals• Lower left on the table

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Nonmetals• Found in all three states• Poor conductors of heat• Poor conductors of

electricity• Solids are brittle• Gain electrons in reactions

to become anions• Upper right on the table

– except H

Sulfur, S(s)

Bromine, Br2(l)

Chlorine, Cl2(g)

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Metalloids

• Show some properties of metals and some of nonmetals

• Also known as semiconductors Properties of Silicon

shinyconducts electricity

does not conduct heat wellbrittle

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The Modern Periodic Table

• Elements with similar chemical and physical properties are in the same column

• Columns are called Groups or Families– designated by a number and letter at top

• Rows are called Periods• Each period shows the pattern of

properties repeated in the next period

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The Modern Periodic Table

• Main group = representative elements = “A” groups

• Transition elements = “B” groups– all metals

• Bottom rows = inner transition elements = rare earth elements– metals– really belong in Period 6 & 7

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= Alkali metals

= Alkali earth metals

= Noble gases

= Halogens

= Lanthanides

= Actinides

= Transition metals

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Important Groups - Hydrogen

• Nonmetal • Colorless, diatomic gas

– very low melting point and density

• Reacts with nonmetals to form molecular compounds– HCl is acidic gas

– H2O is a liquid

• Reacts with metals to form hydrides– metal hydrides react with water to form H2

• HX dissolves in water to form acids

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lithium

sodium

potassium

rubidium

cesium

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Important Groups – Alkali Metals• Group IA = Alkali Metals• Hydrogen usually placed here,

though it doesn’t really belong• Soft, low melting points, low

density• Flame tests ® Li = red, Na =

yellow, K = violet• Very reactive, never find

uncombined in nature• Tend to form water-soluble

compounds, therefore salt is crystallized from seawater then molten salt is electrolyzed

• colorless solutions• React with water to form basic

(alkaline) solutions and H2

2 Na + 2 H2O ® 2 NaOH + H2 • releases a lot of heat

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Important Groups – Alkali Earth Metals• Group IIA = Alkali earth metals• Harder, higher melting, and denser than alkali

metals – Mg alloys used as structural materials

• Flame tests ® Ca = red, Sr = red, Ba = green• Reactive, but less than corresponding alkali metal• Form stable, insoluble oxides from which they are

normally extracted• Oxides are basic = alkaline earth

• Reactivity with water to form H2 – Be = none; Mg = steam; Ca, Sr, Ba = cold water

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Important Groups – Halogens• Group VIIA = halogens• Nonmetals

• F2 and Cl2 gases; Br2 liquid; I2 solid

• All diatomic• Very reactive

• Cl2, Br2 react slowly with water

Br2 + H2O ® HBr + HOBr

• React with metals to form ionic compounds

• HX all acids– HF weak < HCl < HBr < HI

bromine

iodine

chlorine

fluorine

astatine

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Important Groups – Noble Gases

• Group VIIIA = Noble Gases• All gases at room temperature

– very low melting and boiling points

• Very unreactive, practically inert• Very hard to remove electron from or give

electron to

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