Atomic Structure, Bonding, and Periodic Table

Basics

Objective 4TEK 7 The student knows relationships exist between properties of matter and its components.(D) Relate the chemical behavior of an element including bonding, to its placement on the periodic table.

Atoms are the basic unit of chemistry. They consist of 3 smaller things:

•Protons-center (nucleus)

•Neutrons-center (nucleus)

•Electrons-surround in energy levels.

•Protons - these are positively charged (+) •Electrons - these are negatively charged (-) •Neutrons - these have no charge (o)

Each part is arranged in a specific location:

Electrons in the outermost level are called valence electrons.

Number of protons=Atomic number

Number of electrons= Atomic number

Number of neutrons=The mass number – the number of protons.

(NOTE: The mass number of an element is the sum of protons and neutrons in the nucleus.)

Sodium-23 mass number

Carbon-12 mass number

Complete the following chart indicating the number of protons, neutrons and electrons each atom has.

Element Protons Neutrons Electrons

Chlorine-35

Iron-56

Magnesium-24

Lead-208

Nitrogen-14

17 1718

26 30 26

12 1212

82 126 82

7 7 7

are periodic functions of the number of valence electrons an atom has.

Groups or families (vertical column) of elements are listed by increasing atomic number and they have similar chemical properties.

Periods (horizontal rows) of elements usually start with a reactive solid and end with an unreactive gas, called a noble gas. Periods also increase by atomic number.

Properties of Metals: luster, ductile, malleable, good conductors of heat and electricity, lose electrons to form + ions

Metals

Properties of Nonmetals: dull, brittle, insulators (poor conductors), gain electrons to form – ions

Nonmetals

Metalloid (Semimetals) are elements that border the diagonal line between metals and nonmetals. Metalloids have some properties of both metals and nonmetals. They act as a metal with a nonmetal or as a nonmetal with a metal.

Metalloids or semimetals

It’s the valence electrons orbiting in the outer energy level that allow one atom to interact with other atoms so they can be

linked together.

1 valence electron

2 valence electrons

3 valence electrons

4 valence electrons

5 valence electrons

6 valence electrons

7 valence electrons

8 valence electrons

Electrons in the outermost level are called valence electrons.

Loose electrons (+) Accept electrons (-)

occurs typically between a metal and a non-metal. The metal atom loses electrons which are taken by the non-metal. Therefore, the metal ion produced has a positive charge and the non-metal ion is negatively charged.

Sodium +   Chlorine   Sodium Chloride (metal (non-metal (NaCl)

group IA) group VIIA)

occurs when electrons are shared between atoms.

methane(CH4

)

hydrogen gas (H2 )

Water, (H2O)

Covalent bonding occurs between non-metals due to the fact that all of the atoms need to gain electrons, so they have to share.

occurs typically between two metals.

Metals when bonded together have many extra electrons. These extra electrons allow for the conduction of electricity.