Atoms and Ions: Key Concepts Explained

What are atoms considered to be?

• The smallest unit of life

• The basic building blocks of ordinary matter

• The main components of light

• The primary source of energy

What is found at the center of an atom?

• Neutrons only

• Protons only

• Nucleus

• Electron shells

What charge do protons have?

• Negative

• Positive

• No charge

• Neutral

Why are atoms usually neutral in charge?

• They have no protons or electrons

• The number of protons equals the number of electrons

• They have more electrons than protons

• They have more protons than electrons

What is the charge of neutrons?

• Negative

• Positive

• Neutral

• No charge

What is an ion?

• An atom with an equal number of protons and electrons

• An atom that has lost or gained electrons

• An atom with no neutrons

• An atom with more neutrons than protons

How many more electrons does a chloride ion have compared to protons?

• One less electron

• Two more electrons

• Two less electrons

• One more electron

What does the mass number of an element represent?

• The number of neutrons

• The total number of protons and neutrons

• The number of electrons

• The number of protons

What does the atomic number of an element indicate?

• The total number of protons and neutrons

• The number of neutrons

• The number of protons

• The number of electrons

How can you calculate the number of neutrons in an atom?

• Add the atomic number and mass number

• Divide the mass number by the atomic number

• Subtract the atomic number from the mass number

• Multiply the atomic number by the mass number