atoms and elements1

7/26/2019 Atoms and Elements1

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Prepared and Presented by:

Ma. Elizabeth B. Vivar2

PHYSICAL SCIENCEMA. ELIZABETH B. VIVAR

3

PHYSICAL SCIENCE PROF. MA. ELIZABETH B. VIVAR

Elements

Pure substances that cannot be separated into

different substances by ordinary processes

Are the building blocks of matter

Symbols of Elements

Use 1 or 2 letter abbreviations

Capitalize the first letter only

Examples:

C

carbon Co

cobalt

N

nitrogen Br

bromine

4


Symbols from Latin Names

Element Symbol Latin Name

Copper Cu cuprum

Gold Au aurum

Lead Pb plumbum

Mercury Hg hydrargyrum

Potassium K kalium

Silver Ag argentum

Sodium Na natrium

Tin Sn stannum

Tungsten W wolfram

Iron Fe Ferrum

5


Major Elements in the Body

O 65.5% K 0.34%

C 18.0% S 0.24%

H 10.0% Na 0.14%

N 3.0% Cl 0.14%

Ca 1.4% Fe 0.004%

P 1.0% Zn 0.003%

6


Learning Checkpoint

Select the correct symbol for each

A. Calcium

1)

Ca 2) C 3) CA

B. Sulfur

1) Sl 2) S 3) Su

C. Iron

1) Ir 2) F 3) Fe


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7PHYSICAL SCIENCE PROF. MA. ELIZABETH B. VIVAR

Learning Checkpoint

Select the correct name for each

A. N

1)

neon 2) nickel 3) nitrogen

B. Ag

1) silver 2) gold 3) argon

C. Pb

1) lead 2) tin 3) zinc


Periodic Table

The periodic table is an arrangement of the

elements according to similarities, and increasing

atomic number.

There are two groups : 8A Groups , 8B Groups

Vertical column or group

Horizontalrow or period

Groups of Elements

Similar chemical and physical properties

There are 16 groups or family


Groups on the periodic table

1 2 3 4 5 6 7 8


Group I Alkali Metals

Group II Alkaline Earth Metals

Group III Boron

Group IV Carbon

Group V Nitrogen

Group VI Chalcogens

Group VII Halogens

Group VIII Noble Gases

8A - Groups

8B - Groups

All group B (IB

VIII B)


Periods on the periodic table

1

2

3

4

5

6


Periods of Elements

Thereare 7 periodsor series

Period 1 2 elements

Period 2 8 elements

Period 3 8 elements

Period 4 16 elements



Period 7 INCOMPLETE


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Learning Checkpoint

Select the correct element for each

A. Group VII A, Period 4

1)

Br 2) Cl 3) Mg

B. Group II A, Period 5

1) Ag 2) Sr 3) Sn

C. Group V A, Period 3

1) K 2) P 3) Si


Learning Checkpoint

Specify metal (1) or nonmetal (2) for each:

A. sulfur ____

B. chlorine ____

C. sodium ____

D. iron ____

E. carbon ____

F. silver ____

G. Mercury ____


Learning Checkpoint

Select the correct elements:

A. Metals in Group IVA

1) Ge, Sn, Pb

2) C, Si

3) C, Si, Ge, Sn

B. Nonmetals in Period 2

1) He, Ne, Ar

2) N, P, As

3) N, O, F

16PHYSICAL SCIENCEMA. ELIZABETH B. V IVAR

Atomic Number

Mass Number

Subatomic Particles

17PHYSICAL SCIENCEMA. ELIZABETH B. V IVAR

Atomic Number

Mass Number

Subatomic Particles


Atomic Theory

Atoms are building blocks of elements

Similar atoms in each element

Two or more different atoms bond in simple ratios

to form compounds

Sub-atomic Particles

Particle Symbol Charge Relative

Mass

Electron e

-

1- 0

Proton p

+

1

+

1

Neutron n 0 1


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Atomic Number Z)

Is the number of protons in the nucleus of the

atom

11

Na

Atomic Number

Symbol

11 protons

Sodium


Learning Checkpoint

State the number of protons for an atoms of each of

the following:

A. Nitrogen

1)

7 2) 14 3) 5

B. Sulfur

1) 32 2) 16 3) 8

C. Barium

1) 56 2) 137 3) 81


Electrons

An atom is neutral

The net charge is zero

Number of protons = Number of e lectrons

Atomic Number = Number of electrons

11

Na

Atomic Number

Z = 11

p = 11

e = 11


Isotopes

Atoms with the same number of protons, but

different numbers of neutrons.

Atoms of the same element (same atomic

number) with differentmass numbers

Isotopes of chlorine

35

Cl

37

Cl

17 17

chlorine - 35 chlorine - 37


Learning Checkpoint

Naturally occurring carbon consists of three isotopes,

12

C,

13

C, and

14

C. State the number of protons,

neutrons, and electrons in each of these carbon atoms.

12

C

13

C

14

C

6 6 6

p _______ _______ _______

e _______ _______ _______

n _______ _______ _______


Mass Number A)

Is the total number of protons and neutron in the

nucleus of the atom:

A = number neutron + number of protons

A = number of neutrons + Z

11

Na

22.99

Atomic Number

Symbol

Mass Number


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Number of Neutrons

Can be calculated, by subtracting the atomic

number from mass number

35

Cl

17

A

Cl

Z

Can be calculated, by subtracting the atomic

number from mass number

n = A - Z


Calculating Atomic Mass

Percent(%) abundance of isotopes

Mass of each isotope of that element

Weighted average =

mass isotope

1

(%) + mass isotope

2

(%)

100 100


Learning Checkpoint

Cl-35 is about 75.5 % and Cl-37 about 24.5% of

natural chlorine. What is the average atomicmass?

35 x 75.5 = 26.4

100

35.5

37 x 24.5 __ = 9.07

100

28PHYSICAL SCIENCEPROF. MA. ELIZAB ETH B. VIVAR

Practice 1

Gallium is a metallic element found in small laser used

in compact disc players. In a sample of gallium, there

is 60.2% of gallium-69 (68.9 amu) atoms and 39.8 %

of gallium-71 (70.9 amu) atoms. What is the atomic

mass of gallium?


Solution

Ga-69

68.9 amu x 60.2 = 41.5 amu for

69

Ga

100

Ga-71 (%/100)

70.9 amu x 39.8 = 28.2 amu for

71

Ga

100

tomic mass Ga

= 69.7 amu

atoms and elements1

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