how can we describe an atom? how can atoms of the same element be both similar and different at the...

How can we describe an atom?How can atoms of the same element be both similar and different at the same time?What do we call an atom that is not neutral?How can we calculate the average mass of isotopes?How has the model of the atom evolved over time?How can we describe the modern model of the atom?How can we describe where are electrons are located within the electron cloud?How can we describe how electrons are arranged?What is electromagnetic radiation?How is light produced?

- Regents Chemistry

*Do Now

*October 1, 2014

*In your own words describe the term ATOM. Give an example if you can!

*Atomic Theory

*Atomic Theory BP

AIM: How can we describe an atom?

The Theory of the Atom

• ________________, a famous Greek teacher who lived in the 4th Century B.C., first suggested the idea of the atom.

• ________ __________ came up with his atomic theory based on the results of his experiments.

The Atom

• The smallest particle of an ________________ is an atom.

• The atom is made up of three ________________ particles. (1)The electron was discovered in _______ by J. J. Thomson by

using a cathode ray tube. The electron has a _______ charge. It’s mass is much smaller than the other 2 subatomic particles, therefore it’s mass is usually ______________.

Democritus

John Dalton

element

subatomic

1897(−)

ignored

(2) The proton has a ______ charge, and it was discovered in _________ by E. Goldstein.

(3) The neutron does not have a charge. In other words, it is ________. It was discovered in ____ by James Chadwick. The neutron has about the same _________ as the proton.

*These three particles make up all the ____________________ in the Universe!

*There are other particles such as neutrinos, positrons, and quarks, but are typically left for 2nd year chemistry courses.

neutral 1932

mass

visible matter

(+)1886

Nuclear Atomic Structure

*The atom is made up of 2 parts/sections:

(1) The ______________ --- (in the center of the atom)

(2) The ____________ _________ --- (surrounds the nucleus)

nucleuselectron cloud

(p+ & n0)

e− cloud

The Nucleus*Discovered by Ernest ________________ in ________.

*He shot a beam of positively charged “alpha particles”, which are ___________ nuclei, at a thin sheet of ______ _____.

*

• 99.9% of the particles went right on through to the ______________.

• Some were slightly deflected. Some even ____________ ________ towards the source!

• This would be like shooting a cannon ball at a piece of tissue paper and having it bounce off.

Rutherford 1911

helium gold foil

detector

bounced back

(1) Most of the atom is more or less _________ ___________.

(2) The nucleus is very _________. (Stadium Analogy)

(3) The nucleus is very ___________. (Large Mass ÷ Small Volume)

(4) The nucleus is ______________ charged.

empty space

densetiny

positively

Counting Subatomic Particles in an Atom

• The atomic # of an element equals the number of ____________ in the

nucleus.

• The mass # of an element equals the sum of the _____________ and

______________ in the nucleus.

• In a neutral atom, the # of protons = # of ______________.

• To calculate the # of neutrons in the nucleus, ______________ the

___________ # from the __________ #.

protons

protons

neutrons

electrons

subtract

atomic mass

Atomic Models

(1) Model:

• a ball of (+) charge containing a number of e-

• no ________________

• often described as the “________ _______________” atom.

(2) Model:

• a ____________ of (+) charge surrounded by a number of e-

• no _____________ and no e- orbitals

Thomson

nucleus

plum pudding

Rutherford

nucleus

neutrons

(3) Model:

• a nucleus of (+) charge that also contains ______________

• nucleus is encircled by e-’s located in definite orbits (or paths).

• e-’s have ___________ energies in these orbits

• e-’s do not lose energy as they orbit the nucleus

(4) Mechanical Model ( Wave Mechanical Model)

• no definite ____________ to the e- path (“fuzzy” cloud)

• orbits of e-’s based on the _________________ of finding the e- in the particular orbital shape.

Atomic Models

Bohr

neutrons

fixed

Quantum

shape

probability

Bohr Atomic Model

Quantum Mechanical

Model

*Do Now

*October 2, 2014

*Take out your reference table and open up to the Periodic Table

*Complete Questions 1-3 on page 5 of your packet!

(1) Find the # of e-, p+ and n0 for sodium. (mass # = 23)

2) Find the # of e-, p+ and n0 for uranium. (mass # = 238)

3) What is the atomic # and mass # for the following atom? # e- = 15; # n0 = 16

Atomic # = 11 = # e- = # p+ # neutrons = 23-11 = 12

Atomic # = 92 = # e- = # p+ # neutrons = 238-92 = 146

Atomic # = 15 = # e- = # p+ Mass # = p+ + n0 = 15+16 =31

The element is phosphorus!

* An atom can gain or lose electrons to become electrically charged.

* Cation = (___) charged atom created by ___________ e-’s.

* Cations are ______________ than the original atom.

* _____________ generally form cations.

* Anion = (___) charged atom created by _____________ e-’s.

* Anions are ____________ than the original atom.

* _______________ generally form anions.

Practice Problems: Count the # of protons & electrons in each ion.

a) Mg+2 p+ = _____ e− = ______

b) F−1 p+ = _____ e− = ______

+ losing

smaller

Metals

− gaining

larger

Nonmetals

12 10

9 10

REMEMBER P….E….N

Element Name Symbol Atomic

#

AMU # of

Protons

# of

Electrons

# of

Neutrons

K 19 19

5

16

23

10

48

25

14 14

Potassium

39

20

51

Si

32

23

48

25

S

V

10

23

20

5 6115BBoron

Sulfur

Vanadium

Neon

Cadmium

Manganese

Silicon

Ne

Cd

Mn

112

55

28

16

48

14

25

16

19

10

14

16

28

10

64

30

*AIM: How can atoms of the same element be both similar and different at the same time?- Isotopes

*An isotope refers to atoms that have the same # of ___________, but they have a different # of ___________.

*Because of this, they have different _________ #’s (or simply, different ___________.)

*Isotopes are the same element, but the atoms weigh a different amount because of the # of ______________.

Examples---> (1) Carbon-12 & Carbon-13

(2) Chlorine-35 & Chlorine-37

(The # shown after the name is the mass #.)

*For each example, the elements have identical ___________ #’s, (# of p+) but different _________ #’s, (# of n0).

*Another way to write the isotopes in shorthand is as follows:C Cl12

6

35

17

The top number is the ________ #, and the bottom # is the __________ number. Calculating the # n0 can be found by _____________ the #’s!

protons neutrons

massmasses

neutrons

atomic

mass

mass atomic subtracting

Isotopes

(1) Find the # e-, p+ and n0 for Xe-131.

2) Find the # e-, p+ and n0 for

3) Write a shorthand way to represent the following isotope:

# e- = 1 # n0 = 0 # p+ = 1

Cu63

29

Atomic # = 54 = p+ = e− n0 = 131 − 54 = 77

Atomic # = 29 = p+ = e− n0 = 63 − 29 = 34

Atomic # = p+ = e− = 1 mass # = n0 + p+ = 1+ 0 = 1

H-1 or H1

1

*What do we call an atom that is not neutral?How can we calculate the average mass of isotopes?

Element Name

Symbol

Atomic #

Mass # #Protons #Electrons

#Neutrons

17

22

Ar

9

Complete The Chart in your notes

Nucleons: particles in the nucleus (protons and neutrons)

Nuclear Charge: charge of the nucleus (same as # of protons)

Examples:

1.How many nucleons are there in an atom with an atomic number of 20 and 23 neutrons?

2.What is the nuclear charge of an Iron atom?

43

26

*Based on the relative mass of Carbon-12 which is exactly _______.

*1 p+ ≈ __ atomic mass unit (amu) 1 n0 ≈ __ amu 1e- ≈ __ amu

*The atomic masses listed in the Periodic Table are a “weighted average” of all the isotopes of the element.

12

1 1 0

Weighted Average

Practice Problems: (1) Mrs. Smith’s geometry semester grades are calculated using a

weighted average of three category scores: Major Grades= 60% of your gradeMinor Grades= 30% of your gradeSemester Exam=10% of your grade

• If a student had the following scores, what would they receive for the semester?

Major= 80 (B − )Minor= 60 (D −)

Semester Exam=65 (D)

Step (1): Multiply each score by the % that it is weighted.

Step (2): Add these products up, and that is the weighted average!

60% x 80 = 48.0

30% x 60 = 18.0

10% x 65 = 6.5

Add them up!!

A “normal average” would be calculated by simply adding the raw scores together and dividing by 3…

80 + 60 + 65 = 205 ÷ 3 = 68.3 = D

+

72.5 (C−)

Practice Problems:

(2) In chemistry, chlorine has 2 isotopes:

Cl-35 (75.8% abundance) Cl-37 (24.23 % abundance)

What is the weighted average atomic mass of chlorine?

35 x 0.758 = 26.53

37 x 0.2423 = 8.9651

Add them up!!!

(3) Oxygen has 3 isotopes:

O-16 (99.76%) O-17 (0.037%) O-18 (0.2%)

Estimate oxygen’s average atomic mass.

+

35.4951 amu

Barely over 16.0 amu

(4) Copper has an average atomic mass of 63.546 amu.  It contains only two natural isotopes, which are Cu-63, with an isotope mass of 62.940 and Cu-65 with an isotope mass of 64.928.  What are the percent of the two isotopes in naturally occurring copper?

Avg. Atomic Mass = (%Cu-63 x Mass Cu-63) + (%Cu-65 x Mass Cu-65)

63.546 = (%Cu-63 x 62.940) + (%Cu-65 x 64.928)

% Cu-63 + % Cu-65 = 100% % Cu-63 + % Cu-65 = 1OR

Page 13 in your packets # 1 and 2

*Do Now

*October 8th, 2014

*Take out your homework from last night

*Work on “Calculate the atomic mass of each of the following isotopes” it says pg 11 at the bottom!

Diagram:

• The energy levels in an atom are sort of like _________ of a ladder.

• The more energy an electron has, the __________ away from the nucleus it usually will be.

• The energy levels are not evenly spaced. They get ___________ together as you travel farther away.

• To move from one “rung” to another requires a “____________” of energy.

AIM: How can we describe where electrons are located? - Energy Levels

rungs

farther

closer

quantum

continuous energy levels quantized energy levels

*Describe the ______________ of the e-’s around the nucleus.

*Quantum #’s are sort of like a home _____________ for the electron.

*This information about the location of the e-’s in an atom can be used to:

(1) determine chemical & physical _____________ for the elements.

(2) show how the _______________ __________ is organized.

(3) show _____ and _____ elements combine to form compounds.

location

address

properties

Periodic Table

how why

s

s

s

s

p

p

p

f

d

d

Practice Problems:

Write the electron configuration notation for each of the following atoms:

*H

*C

*Fe

*Br

1

2-4

2-8-14-2

2-8-18-7

October 9th, 2014

Complete questions 11-20 on the worksheet I asked you to print last night

*How do electron configurations relate to the chemical and physical properties of an element?

*All elements with the _________ outer shell e- configurations have ________ properties.

*This means that elements in the same ____________ group have similar properties.

Examples: (1) Li, Na, K, Rb, and Cs all have __ lone “__” e- for their last orbital... (_____, _____, _____, etc.) This makes all of them ___________ reactive. They all react with __________ to produce hydrogen gas.

(2) Ne, Ar, Kr, Xe, and Rn all have the outer energy level completely __________ with electrons...(________, ________, ________, etc.) This makes all of them ______________. They do not produce __________________!

same

similar

vertical

1 s2s1 3s1 4s1

very water

filled 2s2 2p6 3s2 3p6

4s2 4p6 inertcompounds

*When atoms get hit with energy (by _____________ them with electricity or by ____________ them up), the electrons absorb this energy and __________ to a higher energy level. Figure (a)

*As they immediately fall back down to the “____________ state”, they give off this energy in the form of a particle of ___________ (or other types of electromagnetic radiation) called a _____________. Figure (b)

zapping

heating

jump

ground

light

photon

*Complete questions 1-10 on the Electron Configuration Worksheet

*October 10th, 2014

*Do Now:

Complete the first page of the electron configuration packet

Valence electrons are the electrons in the last shellKernal electrons are all the electrons other than the ones in the last shell

*Each photon emitted has a specific ___________ (or frequency).

*The color of the light that is given off depends on how _____ the electron _______ (which depends on how big of a jump it originally made.) The farther the fall, the ___________ energy the photon has.

color

far fell

greater

Friday 10/10/14 – D day:

DO NOW: Answer the following questions

1.What is the excited state

2.What is the ground state (where can you find the ground state configurations for a given element

3.What is the ground state configuration for Ne

4.Write a possible excited state for S

5.What happens to electrons as they move from an excited state to the ground state?

*Since electrons are located only in certain __________ levels (or orbitals) around the nucleus, only certain specific _________ of light are emitted.

*Scientists use a _________________ to separate these colors into bands of light. These bands of color look like a ______ code of color which is characteristic of that element. No two elements produce the same ______________ of colors. This can be used to distinguish one element from another contained in a sample. (See Fig. 13.11)

energy

color

spectroscopebar

spectrum

Hydrogen Spectrum

Neon Spectrum

CONCLUSION:

Hydrogen

Helium

Neon

Sodium

Mercury

Emission Spectrum Lab