Elements and the Periodic Table

Front

What is the atomic number of an element based on?

Back

The atomic number of an element is based on the number of protons in its nucleus.

Front

How did Mendeleev arrange the first periodic table?

Back

Mendeleev created the first periodic table by arranging elements in order of increasing atomic mass.

Front

Which elements do not ordinarily form compounds?

Back

The elements that do not ordinarily form compounds are noble gases.

Front

What are the horizontal rows in the periodic table called?

Back

The horizontal rows in the periodic table are known as periods.

Front

What is half-life in the context of radioactive isotopes?

Back

Half-life is the time required for half of the radioactive atoms in a sample to decay.

Front

What is the significance of half-life measurements?

Back

Measurements of half-life make radioactive isotopes useful for determining the ages of rocks and fossils.

Front

What are the main categories of elements in the periodic table?

Back

The main categories of elements in the periodic table are metals, nonmetals, and metalloids.

Front

What is a group in the periodic table?

Back

A group in the periodic table is a vertical column of elements that share similar chemical properties.

Front

What are alkali metals?

Back

Alkali metals are the elements in Group 1 of the periodic table, known for being highly reactive.

Front

What are halogens?

Back

Halogens are the elements in Group 17 of the periodic table, known for being very reactive nonmetals.