Unit 1: Atoms, Ions, and Isotopes

Atomic Structure

1

What are the three subatomic particles in an atom?

protons, neutrons, and electrons

2

Which subatomic particle(s) has/have a positive charge?

protons have a positive charge

3

Which subatomic particle(s) has/have a negative charge?

electrons have a negative charge

4

Which subatomic particles are located in the nucleus?

protons and neutrons

5

Protons and neutrons are approximately ______ times bigger than electrons.

approximately 2000 times bigger

Atoms

1

Which element has 47 protons?

silver (Ag)

2

The atomic number of an element tells you what information?

the number of protons in an atom of that element

3

What does the mass number tell you about an atom?

the number of protons + the number of neutrons

4

(protons in He) + (protons in calcium) + (protons in tin)

2 + 20 + 50 = 72

5

What is the relationship between the protons and electrons when an atom is neutral?

the number of protons is equal to the number of electrons

Ions

1

What is an atom called when it loses electrons?

a cation

>^._.^<

2

An anion is an atom with more _______ than _______.

 more electrons than protons

3

A calcium ion has a +2 charge. How many protons and electrons are in this ion?

20 protons and 18 electrons

4

(electrons in Na⁺¹) + (electrons in S^-2) + (electrons in Fe)

10 + 18 + 26 = 54

5

An ion has a charge of -1 and has 36 electrons. What is the name of this element?

bromine

Isotopes

1

Isotopes of the same element have different numbers of which subatomic particle?

neutrons

2

The mass number of an atom tells you what information?

the mass number = protons + neutrons

3

The isotope of aluminum-27 has how many neutrons?

14 neutrons

4

The isotope of manganese-55 has how many protons and neutrons?

25 protons and 30 neutrons

5

An atom has 15 protons and 17 electrons. Write the proper notation for this isotope.

P-32 or phosphorus-32

Average Atomic Weight

1

A bag of Jolly Ranchers has these candy flavors:

10 sour apple, 20 lemon, 12 cherry, 8 grape.

What is the % of grape and % cherry in the bag?

% grape = (8/50)*100 = 16%

% cherry = (12/50)*100 = 24%

2

What is the formula to calculate the average atomic weight?

Average Atomic Weight = (%#1 / 100)(mass #1)

+ (%#2 / 100)(mass #2) + ...

3

Atom Z has two isotopes with atomic masses of 10.0 amu and 20.0 amu. If the percent abundances are 30% and 70%, respectively, calculate the average atomic weight of atom Z.

(30/100)*(10.0) + (70/100)*(20.0) = 3 + 14 = 17 amu

4

Atom X has three isotopes listed below:

Isotope 1: 21% abundant, 125.2 amu

Isotope 2: 12% abundant, 128.5 amu

Isotope 1: 67% abundant, 130.0 amu

Calculate the average atomic weight of Atom X

(0.21)(125.2 amu) + (0.12)(128.5 amu) + (0.67)(130.0 amu)

= 26.292 + 15.42 + 87.1

= 128.812 amu

5

A bag of Jolly Ranchers has these candy flavors:

10 sour apple (5 amu), 20 lemon (10 amu), 12 cherry (15 amu), 8 grape (20 amu).

Atomic masses are shown in (parenthesis). Calculate the average atomic weight of the Jolly Ranchers isotope.

(10/50)*(5) + (20/50)*(10) + (12/50)*(15) + (8/50)*(20)

= 1+4+3.6+3.2 = 11.8 amu