Atoms & the Periodic Table

Front

What is an atom?

Back

An atom is the smallest unit of matter that retains the properties of an element. It consists of protons, neutrons, and electrons.

Front

What determines the identity of an element?

Back

The identity of an element is determined by the number of protons in its nucleus.

Front

What is the atomic number?

Back

The atomic number is the number of protons in the nucleus of an atom, which defines the element.

Front

What is a mass number?

Back

The mass number is the total number of protons and neutrons in an atom's nucleus.

Front

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

Back

Number of neutrons = Mass number - Atomic number.

Front

What are valence electrons?

Back

Valence electrons are the electrons in the outermost shell of an atom that are involved in chemical bonding.

Front

How many valence electrons does an atom with 4 electrons in its outer shell have?

Back

The atom has 4 valence electrons.

Front

What is ionization energy?

Back

Ionization energy is the energy required to remove an electron from an atom in its gaseous state.

Front

Which element has the highest ionization energy in a given period?

Back

Generally, ionization energy increases across a period from left to right due to increasing nuclear charge.

Front

What is the trend of ionization energy in the periodic table?

Back

Ionization energy increases across a period and decreases down a group.