The Atom
Atomic Number and Mass
Number
Isotopes
LecturePLUS Timberlake

1
Atomic Theory

Atoms are building blocks of elements
Similar atoms in each element
Different from atoms of other elemen...
Subatomic Particles
Particle

Symbol

Charge

Relative
Mass

Electron

e-

1-

0

Proton

p+

+

1

Neutron

n

0

1

Lect...
Location of Subatomic Particles
10-13 cm
electrons
protons
nucleus

10-8 cm

LecturePLUS Timberlake

neutrons

4
Atomic Number
Counts the number
of
protons
in an atom

LecturePLUS Timberlake

5
Periodic Table
Represents physical and chemical
behavior of elements
Arranges elements by increasing atomic
number
Repe...
Periodic Table
1

2

3

4

5

6

7

8

11
Na

LecturePLUS Timberlake

7
Atomic Number on the Periodic
Table
Atomic Number

Symbol

11

Na
LecturePLUS Timberlake

8
All atoms of an element have
the same number of protons
11 protons

Sodium

11

Na
LecturePLUS Timberlake

9
Learning Check AT 1
State the number of protons for atoms of each
of the following:
A. Nitrogen
1) 5 protons
2) 7 protons ...
Solution AT 1
State the number of protons for atoms of each
of the following:
A. Nitrogen
2) 7 protons
B. Sulfur
2) 16 pro...
Number of Electrons

An atom is neutral
The net charge is zero
Number of protons = Number of electrons
Atomic number =...
Mass Number

Counts the number
of
protons and neutrons
in an atom

LecturePLUS Timberlake

13
Atomic Symbols
Show the mass number and atomic number
Give the symbol of the element
mass number
23

atomic number

Na

...
More Atomic Symbols

16

31

O
8

8 p+
8n
8 e-

65

P
15

Zn
30

15 p+
30 p+
16 n
35 n
LecturePLUS
15 e- Timberlake
30 e-
...
Masses of Atoms
A scale designed for atoms gives their small
atomic masses in atomic mass units (amu)
An atom of 12C was...
Atomic Mass

Na
22.99

Listed on the periodic table
Gives the mass of “average” atom of each
element compared to 12C
Av...
Learning Check AT6
Using the periodic table, specify the
atomic mass of each element (round to the
tenths place):
A. calci...
Solution AT6
Using the periodic table, specify the
atomic mass of each element (round to the
tenths place):
A. calcium

_4...
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Atom basics

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Atom basics

  1. 1. The Atom Atomic Number and Mass Number Isotopes LecturePLUS Timberlake 1
  2. 2. Atomic Theory Atoms are building blocks of elements Similar atoms in each element Different from atoms of other elements Two or more different atoms bond in simple ratios to form compounds LecturePLUS Timberlake 2
  3. 3. Subatomic Particles Particle Symbol Charge Relative Mass Electron e- 1- 0 Proton p+ + 1 Neutron n 0 1 LecturePLUS Timberlake 3
  4. 4. Location of Subatomic Particles 10-13 cm electrons protons nucleus 10-8 cm LecturePLUS Timberlake neutrons 4
  5. 5. Atomic Number Counts the number of protons in an atom LecturePLUS Timberlake 5
  6. 6. Periodic Table Represents physical and chemical behavior of elements Arranges elements by increasing atomic number Repeats similar properties in columns known as chemical families or groups LecturePLUS Timberlake 6
  7. 7. Periodic Table 1 2 3 4 5 6 7 8 11 Na LecturePLUS Timberlake 7
  8. 8. Atomic Number on the Periodic Table Atomic Number Symbol 11 Na LecturePLUS Timberlake 8
  9. 9. All atoms of an element have the same number of protons 11 protons Sodium 11 Na LecturePLUS Timberlake 9
  10. 10. Learning Check AT 1 State the number of protons for atoms of each of the following: A. Nitrogen 1) 5 protons 2) 7 protons 3) 14 protons B. Sulfur 1) 32 protons 2) 16 protons C. Barium 1) 137 protons 2) 81 protons LecturePLUS Timberlake 3) 6 protons 3) 56 protons 10
  11. 11. Solution AT 1 State the number of protons for atoms of each of the following: A. Nitrogen 2) 7 protons B. Sulfur 2) 16 protons C. Barium 3) 56 protons LecturePLUS Timberlake 11
  12. 12. Number of Electrons An atom is neutral The net charge is zero Number of protons = Number of electrons Atomic number = Number of electrons LecturePLUS Timberlake 12
  13. 13. Mass Number Counts the number of protons and neutrons in an atom LecturePLUS Timberlake 13
  14. 14. Atomic Symbols Show the mass number and atomic number Give the symbol of the element mass number 23 atomic number Na sodium-23 11 LecturePLUS Timberlake 14
  15. 15. More Atomic Symbols 16 31 O 8 8 p+ 8n 8 e- 65 P 15 Zn 30 15 p+ 30 p+ 16 n 35 n LecturePLUS 15 e- Timberlake 30 e- 15
  16. 16. Masses of Atoms A scale designed for atoms gives their small atomic masses in atomic mass units (amu) An atom of 12C was assigned an exact mass of 12.00 amu Relative masses of all other atoms was determined by comparing each to the mass of 12 C An atom twice as heavy has a mass of 24.00 amu. An atom half as heavy is 6.00 amu. 16 LecturePLUS Timberlake
  17. 17. Atomic Mass Na 22.99 Listed on the periodic table Gives the mass of “average” atom of each element compared to 12C Average atom based on all the isotopes and their abundance % Atomic mass is not a whole number LecturePLUS Timberlake 17
  18. 18. Learning Check AT6 Using the periodic table, specify the atomic mass of each element (round to the tenths place): A. calcium __________ B. aluminum __________ C. lead __________ D. barium __________ E. iron __________ LecturePLUS Timberlake 18
  19. 19. Solution AT6 Using the periodic table, specify the atomic mass of each element (round to the tenths place): A. calcium _40.1 amu _ B. aluminum _27.0 amu _ C. lead _207.2 amu_ D. barium _137.3 amu_ E. iron _55.8 amu__ LecturePLUS Timberlake 19

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