Atomic Structure

Notes

2

Atomic Structure

Subatomic particles include ________, _________ and _________.

protons neutronselectrons________ and

_________ are inside the ________

Protons neutronsnucleus

__________ are found __________ the nucleus

Electronsoutside

Atoms are made up of __________ _________ .

subatomic

particles

3

Subatomic Particles

Protons have a _________ charge and a mass of ________.

Neutrons have a _________ charge and a mass of _________.

Electrons have a _________ charge and a mass that is so ______ that we consider electrons to have ____ mass!

+1 AMU

neutral1 AMU

-small

“NO”

1 AMU = Atomic Mass Unit

4

Number of Protons

Elements in the Periodic Table are organized by ________ ________.Atomic numberThe atomic number is the same as the number of ________.protons

Every element has a _________ number of protons, and therefore a ________ atomic number.

different

different

5

Atomic Number = # protons

6

Number of Electrons

In a _________ atom, the number of _________ always equals the number of __________.

neutralprotonselectrons

#p = #e

7

Electron PracticeFind the number of protons and electrons in the following atoms:

Symbol Protons Electrons

Mg

O

Au

Ti

12 128 879 7922 22

8

Atomic Mass

Proton = ________ amu1An atom’s mass is the sum of its parts

Electron = ________ amuNeutron = ________ amu1

0

Since the electron has practically no mass we don’t count it in the mass of the

atom

9

Atomic Mass

You can find the mass of an atom from the __________ _______Periodic

For us, that mass is the sum of the __________ and __________ .Protons

Table

Neutrons

Fluorine has - __________ protons__________ neutrons

910

10

Atomic Mass = # protons + # neutrons

11

Number of Neutrons

To get the number of neutrons, get the atomic mass from the _________ ______ and subtract from that the number of ________.

Periodic

#neutrons = Atomic Mass - #p

Table

protons

12

Neutron PracticeFind the number of p, n and e in the

following atoms:Symbol Protons Neutrons Electrons

Na

B

H

C

11 115 51 16 66

06

12

13

14

Element Symbols

Every element has a _________ on the Periodic Table.

symbol

The symbol is either 1 or 2 letters, where the first is always a _________ letter, and the second is always a _______ letter…

CAPITALsmall

H He C Ca

15

Element Notation

Element symbols contain the atomic number, mass number and element

symbol.

J Massnumber

Atomicnumber

Element symbol

16

Element NotationComplete the notation for the following:

K Al19

39

13

27

The Bohr Model

The ________ is in the center of the atom

and contains both _________ and

__________, and the ___________ are found

orbiting the nucleus.

nucleus

protons

electronsneutrons

Basic Layout

Electron Energy Levels

• Electrons are found in _______ levels

around the nucleus.

energy

• The _______ to the nucleus, the ________

the energy of the electrons.

closer lower

• The _______ from the nucleus, the

________ the energy of the electrons.

farther

higher

Electron Configuration

Electron configuration is the ___________ of

electrons outside the nucleus of an atom.

arrangement

The 1st energy level holds up to

____ electrons.

82nd level holds up to ___

3rd level holds up to ___18

2

Electron ConfigurationYou don’t have to memorize this, use the Periodic Table

Look under the atomic number and you will see where the electrons will goFor Oxygen, there are ___ electrons in the 1st level and ___ electrons in the 2nd level.

2

6

How to: Bohr ModelsRules

1. Put the number of _______ in the ________protons nucleus

2. Put the number of _________ in the ________neutrons nucleus

3. Put a dot for each electron in the ______ energy level (Max of __ ) and then move on to the second if necessary.5. Put a dot for each electron in the _______ energy level (Max of __ ) and then move to the third if necessary.

first2

8second

6. Repeat for the third level if necessary

22

Practice: Bohr ModelsDraw the Nucleus – make sure it is big enough to write inside

Add the protons and neutrons to the nucleus

3p4n

Draw the first energy level and put a dot for each electron on that level (Max of 2)

Li

Draw the second energy level and put a dot for each electron on that level (Max of 8)

Notice the yellow electrons – these are Valence Electrons (e- on the outermost shell)

23

Practice: Bohr ModelsDraw the Nucleus – make sure it is big enough to write inside

Add the protons and neutrons to the nucleus

13p14n

Draw the first energy level and put a dot for each electron on that level (Max of 2)

Al

Draw the second energy level and put a dot for each electron on that level (Max of 8)

Draw the third energy level and put a dot for each electron on that level (Max of 18)

Notice the yellow electrons – these are Valence Electrons (e- on the outermost shell)

What are they?

Why are they important?

Review: Valence Electrons

Electrons on the outermost energy level

They are the only electrons involved in chemical reactions

How do you know how many an atom has?On the Periodic table, below the atomic number

Electron Dot diagrams, (also called ______ Dot diagrams) show only the _________ electrons in an atom.Lewisvalence

It includes the ______________ and the _______ of valence electrons.

element symbolnumber

Let’s figure out the ‘rules’ for drawing Lewis/Electron Dot Diagrams…

Lewis Dot Diagrams

1. The first __ valence electrons go on the _____ side of the element symbol.

2top

H He

Rules - Lewis Dot Diagrams

2. Electrons are added ____ at a time in a _________ direction as seen below.

oneclockwise

J1 2

Rules - Lewis Dot Diagrams

3

4

5 6

7

8

28

p=n=

910

Identify the atom above

Electron Movement

We already learned that electrons are located on specific _______ ______ outside the nucleus

The electrons closer to the nucleus have ______ energy and need to _______ energy to get farther away from the nucleus.

lower absorb

Electron Energy

energy

levels

Electron Movement

When you look on the periodic table, you get the _______ state electron configuration

ground

If exposed to enough _____ or __________ energy, electrons can _______ energy and jump up an energy level and become ______.

heat

electricalabsor

b excited

32

The excited state is __________, and really quickly the electron will _____ back down to where it came from and give off the energy it absorbed.

Electron Movement

temporary dro

p

THINK OF A YOUNG KID AFTER EATING CANDY!

Electrons will release energy as ______.

Since each energy level jump has a different _______ of energy, the energy given off will be a different ______ of light.

light

amount colo

r

Energy Released

Normal LightWhite light is made of ____ the colors of the ___________________.

allcontinuous spectrum

Passing light through a ______ separates the light into individual ________ – each having its own ______________.

prism

colors

wavelength

Bright-Line SpectraEach element gives off different ________ of energy – this produces a unique _______ of ______ and ________ that we call a __________ spectrum.

amountspattern lines

colors bright-linen = 3n = 4

n = 2n = 1

Bright-line SpectraThey are formed when atoms ______ (give off) __________.

emitenergy

Each element produces a ________ pattern.unique

37

Unknown Spectra

Flame Test lab

Spectroscopy lab

BELL RINGER

Unknown

What element is the unknown?

IsotopesIsotopes are atoms of the same ________ that have different numbers of ________ and therefore different ________.

elementneutrons

masses

How many neutrons do each of the carbon atoms to the right have?

Isotope ProblemsLet’s practice…

1HMass =#p=#n=

2H 3HMass =#p=#n=

Mass =#p=#n=

110

211

31

2

43

Practice

Ions

Ions have the same number of _______ but a different number of _________.

protonselectrons

This makes an ion a ________ particle, since there aren’t the same number of ________ and _________.

charged

protons electrons

Not or

Calculating ChargeRemember: Electrons are negative!

The charge of the ion is always written here

If the _____ has more electrons it is _____!

Cl-1

If the _____ has more protons it is _____!

ionion

-+

Ion Practice

Figure out the electrons for each of the following ions

Na+1 S-2 Al+3 F-1

#p = 11

#e = 10

#p = 16

#e = 18

#p = 13

#e = 10

#p = 9

#e = 10

47

Practice