2.1 Review

Elements and Atoms

100

Particles found in the nucleus of an atom

Protons and Neutrons

200

______ have positive charges

______ have negative charges

______ have neutral charges

Protons

Electrons

Neutrons

300

The number representing the number of protons in the nucleus

Atomic Number

400

The number of protons and neutrons combined

The atomic mass

500

How do you find the number of neutrons in an atom using the average atomic mass on the periodic table?

Round the average atomic mass and subtract the number of protons

Isotopes

100

What is an isotope?

Atoms of the same element with different numbers of neutrons

200

The number on the bottom of the isotope symbol?

The atomic number

300

The number on the top of the isotope symbol

The atomic mass

400

How many protons and neutrons are in the following isotope?

⁹₆C

3 neutrons

6 protons

500

Why are neutrons important in the nucleus?

Neutrons keep protons separated so they don't repel

Alpha Decay

100

What is radioactive decay?

Occurs when the nucleus of an atom is unstable

200

What does the nucleus give off in alpha decay?

2 Protons 

2 Neutrons

Also called an alpha particle

300

Why is the conservation of matter important for radioactive decay?

The number of protons and the mass number need to add up to the same amount on both sides of the arrow

400

Complete the following alpha decay reaction:

¹¹⁹₅₀Sn --> ____ + _______

¹¹⁹₅₀Sn -> ¹¹⁵₄₈Cd + ⁴₂He

500

Complete the following alpha decay reaction:

²³⁵₉₆Cm -> ^A_ZX + ⁴₂He

²³⁵₉₆Cm -> ²³¹₉₄Pu + ⁴₂He

Beta Decay

100

What happens in beta decay?

A neutron is turned into a proton and an electron is given off

200

The charge of a beta particle

Negative

300

How to do a beta decay equation

Add one to the atomic number and keep the atomic mass the same

400

Complete the following beta decay reaction:

^A_ZX -> ¹⁴₇N + ⁰_-1e

¹⁴₆C -> ¹⁴₇N + ⁰_-1e

500

Complete the following beta decay reaction:

¹⁴¹₅₅Cs -> ^A_ZX + ⁰_-1e

¹⁴¹₅₅Cs -> ¹⁴¹₅₆Ba + ⁰_-1e

Ions

100

What is an ion?

Atoms or molecules with a postive or negative charge

200

Taking away (losing) an electron from an atom results in this particle with what kind of charge?

Caton with a positive charge

300

Adding (gaining) an electron from an atom results in this particle with what kind of charge?

Anion with a negative charge

400

How many protons, neutrons, and electrons does this ion have?

¹⁶₈O^2-

8 protons

8 neutrons

10 electrons

500

Give the symbol, atomic number, atomic mass, and electrons for the following isotope:

Calcium 42

Symbol: ⁴²₂₀Ca²⁺

Atomic number: 20

Atomic mass: 42

Electrons: 18