1 23 i can count atoms and elements

Chemical Bonds

I. Why Atoms Combine

♦ Chemical Formulas

♦ Chemical Bonds

♦ Stability

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Covalent vs. Ionic bonds quick review 3 weeks of school
ionic bonding

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H2O

2 hydrogen atoms

1 oxygen atom

A. Chemical Formula

• Shows:

1) elements in the compound
2) ratio of their atoms[how many of each type of atom]

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Fill in the Blanks

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Fill in the Blanks

Multiple Choice

How many atoms of Hydrogen are in H₂O

• 1

• 2

• 3

• more than 3

Multiple Choice

How many different elements are present in H₂COCH₂

• 5

• 4

• 3

• 2

• chicken salt

Multiple Choice

The ______ are numbers found on the lower right-hand side of an element symbol.

• Coefficient

• Exponent

• Multiplier

• Subscript

Multiple Choice

Coefficients in chemical formulas...

• Multiply just the first atom

• Add to the subscripts at the end of the molecule

• Multiply elements without subscripts

• Multiply EVERYTHING!

Multiple Choice

4CF₂Cl₂

• C = 4, F = 4, Cl = 2

• C = 1, F = 8, Cl = 8

• C = 4, F = 8, Cl = 8

• C = 1, F = 4, Cl = 8

Multiple Choice

C₃H₅(NO₃)₃

• C = 3, H = 5, N = 3, O = 9

• C = 3, H = 5, N = 1, O = 9

• C = 9, H = 15, N = 3, O = 9

• C = 9, H = 15, N = 1, O = 3

Multiple Choice

H₂SO₄

• H = 2, S = 4, O = 4

• H = 2, S = 1, O = 4

• H = 8, S = 4, O = 4

• H = 2, SO = 4

Multiple Choice

A ______ is a number written in front of a chemical formula.

• Coefficient

• Subscript

• Exponent

• Coordinator

Multiple Choice

How many Hydrogen atoms are in 4H₂O?

• 6

• 8

• 2

• 4

Multiple Choice

How many atoms are present if there is no subscript following the element symbol?

• 0

• 2

• only 1

• 1 million

B. Chemical Bond

• Strong attractive force between atoms or ions

in a molecule or compound.

• Formed by:

– transferring e- (losing or gaining)

– sharing e-

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C. Stability

• Stability is the driving force or main reason

behind bond formation. ___ is stable ?

• Elements can [1]gain, [2]lose or [3]share

electrons to become stable-

• Octet Rule

– most atoms form bonds in order to have 8 valence e-

– want a full outer energy level-

(takes 8 to get a full belly) except for1st period babies _____?

– like the Noble Gases all have 8 VE

except for baby ______whose outer shell/belly can only 2 ?

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Multiple Choice

What is the best definition of valence electrons?

• The outermost electron NOT involved in chemical reactions

• The innermost electrons involved in chemical reactions

• The outermost electrons involved in chemical reactions.

• The innermost electrons NOT involved in chemical reactions

Multiple Choice

Each of the following elements attains a stable valence shell WITHOUT having an octet in its outermost shell EXCEPT _______.

• lithium

• hydrogen

• beryllium

• helium

• nitrogen

Open Ended

on a scale from 1 to 10 how confident are you with counting elements and atoms in a chemical formula.

10 is 100% confident