7.4 Using the Bohr Theory

BOHR DIAGRAMS Practice (worksheet)

Draw Bohr Diagrams for:

hydrogen

sodium

phosphorus

neon

calcium

First shell: 2 electrons

Second shell: 8 electrons

Fourth shell: 8 electrons

Third shell: 8 electrons

•When a neutral atom gains or loses electrons

BOHR DIAGRAMS for Ions

NEUTRAL ATOM

ION

How many electron(s)?

How many electron(s)?

How many protons?

How many protons?

OVERAL charge?

OVERAL charge?

Patterns of Electron Arrangement in Groups

Which group has a STABLE OCTET in its outer most

shell?

If there are 8 electrons in the last shell = STABLE OCTET

1 exception = HELIUM (2 electrons)

ATOMS WANT TO HAVE A STABLE OCTET!!!!!! ALL THE TIME!!

All ATOMS want to be

like

NOBLE GASES!

If there are 8 electrons in a shell = STABLE OCTET

Valence Shell = OUTERMOST SHELL

VALENCE ELECTRONS

Electrons in the VALENCE SHELL are called VALENCE ELECTRONS

How many VALENCE ELECTRONS in GROUP 1?

How many VALENCE ELECTRONS in GROUP 2?

How many VALENCE ELECTRONS in GROUP 16?

How many VALENCE ELECTRONS in GROUP 18?

What Do You Notice about the Number of Valence Electrons for

Elements in the Same Group?

Most elements in the same group have the same

number of valence electrons

What Do You Notice About the Placement and the Number of Valence

Electrons for Elements in the Same Period?

Elements in the same period have valence electrons in the same

shell AND the number of valence electrons is increasing going

left to right within the group by one

What Do You Notice About the period number and the number of occupied

shells for Elements in the Same Period?

The period number indicates the number of shells

that have electrons.

All ATOMS want to be

like

NOBLE GASES!

If there are 8 electrons in a shell = STABLE OCTET

ATOMS WANT TO HAVE A STABLE OCTET!!!!!! ALL THE TIME!!

Unreactive because their atoms have filled valence shells =

they are stable = NOBLE GAS STABILITY

NOBLE GASES!

UNREACTIVE = they do not lose or gain electrons

Each atom wants to have as many of valence electrons as the nearest noble gas.

Metals want to

LOSE ELECTRONS

How Do Atoms Become Ions? Atoms WILL gain or lose electrons because they want to be as stable as the NEAEREST

NOBLE GAS

An atom of any metal can lose electrons and form

positive ions

Each atom element to have as many of

valence electrons as the nearest noble gas.

Non - Metals

want to GAIN

ELECTRONS

How Do Atoms Become Ions? Atoms WILL gain or lose electrons because they want to be as stable as the NEAEREST

NOBLE GAS

An atom of any non-metal except a noble gas can

gain electrons and form negative ions

How many electrons

does sodium, Na,

want to have?

10 electrons

Each atom element to have as many of

valence electrons as the nearest noble gas.

How many electrons

does oxygen, O, want

to have?

10 electrons

Each atom element to have as many of

valence electrons as the nearest noble gas.

How Do Atoms Become Ions? Atoms WILL gain or lose electrons because they want to be as stable as the NEAEREST

NOBLE GAS

Ions have the same electron arrangement as the

nearest noble gas

What Element is this?

18 p

22 n

argon

Bohr Diagrams Worksheet

1. How many protons does this element have?

2. How many electrons does this element have?

3. How many valence shells does this element have?

4. How many valence electrons does this element have?

5. How many occupied shells does this element have?

6. What is the identity of this element?

BOHR DIAGRAMS Practice (worksheet)

Draw Bohr Diagrams for:

hydrogen

Sodium ion

Phosphorus ion

Neon ion

calcium ion

First shell: 2 electrons

Second shell: 8 electrons

Fourth shell: 8 electrons

Third shell: 8 electrons

MOLECULES and IONIC COMPOUNDS

Atoms combine with different atoms to form compounds (thanks to electrons)

Forces that hold atoms together are called CHEMICAL BONDS

SHARING ELECTRONS DONATING ELECTRONS

Covalent Bonds Ionic Bonds

Atoms combine with different atoms to form compounds (thanks to electrons)

Forces that hold atoms together are called CHEMICAL BONDS

MOLECULES IONIC COMPOUNDS

Covalent Bonds Ionic Bonds

MOLECULES and IONIC COMPOUNDS

These bonds arise when

VALENCE ELECTRONS interact

Each atom attempts to have

as many of valence electrons

as the nearest noble gas.

MOLECULES and IONIC COMPOUNDS

Forces that hold atoms together are called CHEMICAL BONDS

IONS Atom or a group of atoms with net negative or

positive charge

POSITIVELY CHARGED ION =

NEGATIVELY CHARGED ION =

CATION ANION

IONIC COMPOUNDS Formed by an attraction of positively charged ion and

negatively charged ion

Chemical formula

IONIC COMPOUNDS Formed when electrons are transferred from a metal to

a non - metal

Chemical formula

IONS Cations and Anions are attracted to each other

IONIC BONDING

Draw the Bohr model diagram for NaCl

Draw the Bohr model diagram for NaCl

Draw the Bohr model diagram for NaCl

Draw the Bohr model diagram for KF

Draw the Bohr model diagram for CaF

MOLECULES and IONIC COMPOUNDS Atoms combine with different atoms to form compounds

(thanks to electrons)

Forces that hold atoms together are called CHEMICAL BONDS

SHARING ELECTRONS DONATING ELECTRONS

Covalent Bonds Ionic Bonds

Covalent Bonds Valence Electrons are shared between atoms

Covalent Bonds • Unpaired electronsfrom each atom will pair together, forming a covalent bond.

• These two electrons are sometimes called a bonding pair.

hydrogen fluorine

+

electrons are

shared

Hydrogen

fluoride

BONDING pair of

electrons

Covalent Bonds • An unpaired electron from each atom will pair together, forming a covalent bond.

• These two electrons are sometimes called a bonding pair.

F2 CF4 H2