Midterm Review

Front

Which particles form the nucleus of the atom?

Back

Protons and neutrons.

Front

What is a pure substance?

Back

A material that has a constant composition and consistent properties throughout.

Front

What is the shortcut electron configuration for iodine?

Back

[Kr]5s²4d¹⁰5p⁵.

Front

Do atoms with different numbers of protons belong to the same element?

Back

No, because they have different numbers of protons.

Front

What is the half-life of a substance?

Back

The time required for half of the substance to decay.

Front

How much of a 80g sample of Iodine-125 remains after 100 years?

Back

5 grams.

Front

What is the atomic number of an element?

Back

The number of protons in the nucleus of an atom.

Front

What defines a chemical element?

Back

A substance that cannot be broken down into simpler substances by chemical means.

Front

What is the difference between an atom and an ion?

Back

An atom is neutral, while an ion has a net charge due to the loss or gain of electrons.

Front

What is the significance of the periodic table?

Back

It organizes elements based on their atomic number and properties.