Front

Why were there blank spaces left in Mendeleev's periodic table?

Back

Undiscovered elements not yet known.

Front

What is the mass of 4.98 x 10^24 atoms of Zn?

Back

541 g

Front

How many atoms would be contained in 454 grams of iron (Fe)?

Back

4.90 x 10^24 atoms

Front

Is crumpling a piece of paper a physical or chemical change?

Back

Physical

Front

The number of periods and groups in the periodic table are______?

Back

7, 18

Front

What is the atomic number of an element?

Back

The number of protons in the nucleus of an atom.

Front

Define a physical change.

Back

A change that affects one or more physical properties of a substance without altering its chemical composition.

Front

Define a chemical change.

Back

A change that results in the formation of new chemical substances.

Front

What is the significance of the mole in chemistry?

Back

It is a unit that measures the amount of substance, defined as containing exactly 6.022 x 10^23 particles.

Front

What does the term 'periodic law' refer to?

Back

The properties of elements are a periodic function of their atomic numbers.