Atoms and Bonding

Atoms and Bonding

What is a chemical bond?

The joining of 2 or more atoms.

Why do they bond? To get a full outer
energy level

because it takes less energy

What part of the atom makes bonds?

What part of the atom makes bonds? valence

electrons

Valence electrons:

Electrons in the outer energy level that make
bonds

How do we know how many valence e- each atom has?

How do we know how many valence e- each atom has?

The group number of the element

Lewis structure:A diagram that shows valence
electrons

Lewis structure:

Made up of 1. atomic symbol and

Lewis structure:

2. dots to show valence e- (there is a pattern to
follow)

Ex:Write down the following chemical symbols.

Li

B

N Cl Mg Si Se Ne

We will draw the Lewis structures for the following
atoms on your notes paper.

Li

B

N

Cl

Mg

Si

Se Ne

Always CIRCLE the pairs of e-

NONBONDING PAIRS:

Full pairs of e- that do NOT bond.

UNPAIRED electrons are bonding e-

Octet Rule

Octet Rule:

Atoms WANT a full outer energy level!!!!

Octet Rule:

Atoms WANT a full outer energy level!!! (Usually 8e-)

WHY???? It takes LESS ENERGY!!

Many atoms tend to gain or lose e-

to follow the octet rule.

–

Number of electrons each energy level can hold:

1st energy level: 2

2nd energy level: 8

3rd energy level: 8

CHANGES IN ATOMS:

1. Ions: An atom that gains or loses electrons causing it to

have a negative or positive charge.

Ion: An atom that gains or loses electrons to fill

the outer energy level and has a + or - charge.

Gaining electrons makes - ions

called an aNion

Losing electrons makes + ions

called a cation

How many electrons will an atom gain or lose
when it becomes an ion?

Enough to get a full outer energy level

How many electrons will an atom gain or lose
when it becomes an ion?

Enough to get a full outer energy level (Octet
Rule)

Atoms with NO pairs of valence e- will lose them
and become +

lose them and become +.

Atoms with pairs of valence e- will gain e- to have
full pairs and become -

gain e- to have full pairs

and become -.

Ion Notation:

Superscript: small number written to show the
charge on an ion.
superscript

Al+3

Written up and to the right of the atomic symbol
and shows

Practice:

Li1+

Ca??

Al??

K??

F1-

S??

As??

Br??

the charge (+ or -) and the number of the ion’s
charge.

Practice:

Li+1

Ca??

Al??

K??

F-1

S??

As??

Br??

+ Charge = # of e- it loses (no pairs)

- Charge = # of e- it gains (pairs)

Practice: Draw the Lewis structure AND write the ion notation for
the following elements. They are all in period 4.

As

Ca

Br

Ga

K

Se

Multiple Choice

What part of the periodic table tells you the number of valence electrons?

• period number

• atomic number

• group number

• atomic mass

Draw

Draw the Lewis Structure for Aluminum

Draw

Draw the Lewis Structure for Potassium

Draw

Draw the Lewis Structure for Argon

Multiple Choice

Gaining electrons makes an atom have what charge?

• negative

• positive

• neutral

Multiple Choice

Atoms with NO pairs of electrons will ________ electrons

• gain

• lose

Draw

Draw the Lewis Structure for Magnesium and write it's ion notation.

Draw

Draw the Lewis Structure for Chlorine and write it's ion notation.

MAKING BONDS:

Ions and atoms bond to make compounds and
molecules

Writing Chemical formulas:

Subscripts: small numbers written to show the
number of

Writing Chemical formulas:

ions or atoms of each element in the compound.

Written down and to the right of the element
symbol.

Draw

Write the chemical formula for 2 carbon atoms and 6 hydrogen atoms

Draw

Write the chemical formula for 1 carbon atom, 3 chlorine atoms, 1 fluorine atom

Draw

Write the chemical formula for 1 sodium atom, 2 hydrogen atoms, 2 oxygen atoms

Draw

Write the chemical formula for 2 potassium atoms, 1 sulfur atom, 2 oxygen atom

Ionic Bonds:

+ and - ions join together because of opposite
charges.

Ionic bonds are between a metal and a nonmetal

Ionic bond = Metal + Nonmetal

These bonds form ionic compounds that have a
total charge of 0.

These bonds form ionic compounds that have a
total charge of 0.

Na+1+Cl-1

NaCl

Mg+2 +Cl-1 MgCl2

How Atoms Bond

Ted-Ed

How atoms bond - George Zaidan and Charles Morton

Ionic bonds til 1:11

Covalent Bonds:

Atoms share electrons in order to fill the outer
energy level.

The electrons orbit around 2 atoms, holding them
together.

Very STRONG!!!

covalent bond = nonmetal + nonmetal

Covalent Bonds:

Covalent bonds form between nonmetal and
nonmetal atoms.

These bonds are strong and make molecules.

Very STRONG!!!

The number of covalent bonds an atom makes

equals the number of e- it needs

to fulfil the octet rule

or get a full outer energy level.

Covalent bonds are shown as circles between the

Lewis structures of the elements in a molecule.

Each circle counts as 2 electrons.

H

O

H

Every atom in the molecule MUST have enough

e - to have a full outer energy level.

Ex.

Bigger atoms don’t share electrons evenly.

Creates a molecule with - and + sides.

They are called polar molecules.

Ex. water - most common

How can we use the Periodic Table to determine what
type of bond an atom/element will make???

Sci Show on Bonding

4:16-9:26

Periodic Trends - What can the table tell us?

Radius

Periodic Trends - What can the table tell us?

Atomic Radius - size of atom measured from center of the
nucleus to outer edge of the e- cloud

Quick Monday Periodic Trends Review

1. The amount of energy needed to remove an e- is
2. The distance from the nucleus to the outer e.l. Is
3. An atom’s ability to attract e- is its
4. Which of these (1,2 or 3) increases as you go

DOWN the periodic table?

5. Which of these increases as you go ACROSS the

periodic table?

Review

1. Atoms bond to have a __ __ __ __ because it takes __ __.
2. Valence e- are in the __ __ __ and make __.
3. The number of valence e- on an atom is shown in the __ __.
4. A Lewis structure is a __ that shows __ __.
5. Draw the Lewis structures for F(9) / B(5) (circle pairs)
6. The __ __ says that atoms want a full outer energy level.
7. Write the number of electrons each energy level can hold.

1st__

2nd __

3rd __

8. An atom that loses or gains e- becomes an __.
9. If it gains electrons it gets a __ charge.

10. Write the Lewis structure & ion notation for an ion of nitrogen.

1. Write symbols for 2 elements that make +1 ions.
2. Write symbols for 2 elements that make +3 ions.
3. Write symbols for 2 elements that make -2 ions.
4. Write symbols for 2 elements that make -3 ions.
5. When you add the charge of the + ion and the

- ion in an ionic compound, what is the total
charge?

6. What will the formula be for Calcium chloride?

Ionic Compound Review:

1. C14H18N2O5 Tell the number of atoms of C_ H_ N_ O_
2. Write the formula of a molecule that has 6 carbon, 14 hydrogen,
two nitrogen, 2 oxygen

3. Atoms gain or lose e- to have a _ _ _ _ because it takes _ _.
4. An atom that gains e- has a _ charge and is called a __.
5. An atom that loses e- has a _ charge and is called a __.
6.Write the symbols for Potassium(19) & Selenium(34)

Write below them if they are a M(metal) or NM(nonmetal)

Draw the Lewis Structure for each.

Write the ion notation for each.

Write the correct chemical formula for the compound they will form.

Periodic Trends - Where is the smallest atom?

Atomic Radius

Periodic Trends - Where is the smallest atom?

smallest

Atomic Radius

Periodic Trends - What happens as you go down?

Atomic Radius

Periodic Trends - The size increases.

Atomic Radius

Periodic Trends - What about horizontally? Right to Left

Atomic Radius

Periodic Trends - What about horizontally? Right to Left

Atomic Radius

Periodic Trends - Which atom is biggest?

Atomic Radius

Periodic Trends - Biggest atom!

biggest

Atomic Radius

Periodic Trends - What can the table tell us?
Ionization energy: the amount of energy needed to
remove an e- from an atom

What happens to Ionization Energy as you go from Left to Right?

Use

BLUE

What happens to Ionization Energy as you go Down the table?

It DECREASES What direction do you go to have it INCREASE?

It also INCREASES when you go up diagonally.

I
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Chlorine has the highest Ionization Energy

I
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c
r
e
a
s
e
s

What does that mean? Chlorine holds onto its e- the best.

I
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Periodic Trends - What can the table tell us?
Electronegativity: an atom’s ability to attract e- in a
covalent bond

What happens to electronegativity as you go across from
Left to Right?

Use
GREEN

What happens to electronegativity as you go UP?

What happens to electronegativity as you go UP?

I
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a
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e
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Fluorine - Highest Electronegativity

I
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a
s
e
s

It has the highest ability to attract e- from other atoms

I
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Friday Review Quiz - 10 points

1. Do the following for Boron: A. Draw the Lewis structure.

B. Write the ion notation. C. Tell if it is a cation or anion.

2. Do the following for Sulfur: A. Draw the Lewis structure.

B. Write the ion notation. C. Tell if it is a cation or anion.

3. The number that shows the charge of an ion in ion notation is

called a ______script.

4. The number that shows the number of ions in a formula,

Al2O3is called a ____script.

5. Why do atoms gain or lose electrons?

6. How many e- do atoms want in the 2nd and 3rd energy levels?

Quickie Notes Review

1.Why do atoms make bonds?

2. What part of the atom makes the bonds?
3. How many e- can be held in energy levels 1_, 2_ & 3_
4. When an atoms loses or gains e- it becomes an __.
5. Atoms with ____ gains e- and atoms with __ lose e-

6. The total charge on an ionic compound is ___
7. Covalent bonds form when atoms ____ ___.

Review

1.

The joining of 2 or more atoms is a ____ ___.

2.

Valence electrons are found in the _____ ______ ______.

3.

Valence electrons are drawn in a diagram called a ____ ____.

4.

The number of valence electrons can be found on the periodic table
by using the ____ _____.

5.

Bonding electrons are the ________ electrons.

6.

The Octet Rule says that atoms want a ____ ____ ____ ____.

7.

How will Calcium (Ca/20) obey this rule? gain or lose

8.

It will become a cation/anion. (Choose one.)

9.

How will Bromine (Br/35) obey this rule? gain or lose?

10.

It will become a cation/anion. (Choose one.)

Monday Quick Notes/Brain Review 1/25/2021
1.Atoms make bonds to get a _ _ _ _ because it takes _ _

2. How many e- can be held in the 1st_, 2nd_ &3rd_ energy
levels?

3. In covalent bonds, atoms ___ their electrons.

4. Covalent bonds form between __ and __ atoms.

5. How do you know the number of covalent bonds an atom will
make?

Thursday/Friday Quick Notes Review 10/31/2019
1.Why do atoms make bonds?

2. What part of the atom makes the bonds?

3. How many e- can be held in energy levels 1_, 2_ & 3_

4. When an atoms loses or gains e- it becomes an __.

5. Atoms with ____ gains e- and atoms with __ lose e-

6. The total charge on an ionic compound is ___

7. Covalent bonds form when atoms ____ ___.

What do we know about bonds? 11/1/2019

1. Why do atoms bond?
2. Name 2 types of bonds.
3. Which type of bond is just an attraction of - & +?
4. Which type of bond shares electrons?
5. Which type of bond is stronger?

Chemical Bonds Practice 1/28/21

1. Label I if ionic or C if covalent.
2. Draw Lewis Structure
3. If I - write ion notation for each

If C - draw the lines to show the bonds

A. CS2
B. CaCl2
C. H2PF
D. K3N

Quick Monday Review 10/10/22

1. Draw a model of a Sulfur atom. Include the correct

number of P+, N, energy levels and e- and place
everything in the correct area of the atom.

2. What would be the charge on a S ion?
3. Name an element the S ion would bond with.
4. Name an element the S atom would make a covalent

bond with.

5. Show a covalent bond between S and that element.

Draw Lewis structures and circle shared e-

The Periodic Table - one more time!!

Hank Green

Changes in atoms:

Atoms with the same number of protons

but different numbers of neutrons.

Same atomic number

But different atomic mass

12

13

14

2. Isotope: An atom that gains neutrons causing it to
be unstable so it tends to break apart.

Unstable atoms

This is called radioactivity.

Radioactive atoms