Atoms and Elements

Flashcards about Atoms and Elements

What are atoms?

The smallest particles of matter that cannot be broken down further by chemical means.

What is an element?

A substance that contains only one kind of atom.

What is the Periodic Table?

A table that gives the names and symbols for all the elements.

What do the columns in the Periodic Table represent?

Families or groups of elements with similar properties.

What do the rows in the Periodic Table represent?

Periods.

What is the zig-zag line in the Periodic Table?

It separates metals from non-metals.

What subatomic particles make up the atom?

Protons, neutrons, and electrons.

What are the charges of protons, neutrons, and electrons?

Protons have a positive charge, neutrons have no charge, and electrons have a negative charge.

What is the proton number?

The number of protons in an atom, which identifies the atom.

Why do atoms have no overall charge?

Because they have an equal number of protons and electrons, so the positive and negative charges cancel out.

What are nucleons?

Protons and neutrons, which form the nucleus.

What is the nucleon number?

The total number of protons and neutrons in an atom.

What are isotopes?

Atoms of the same element with different numbers of neutrons.

What does it mean for an isotope to be radioactive?

Its nucleus is unstable and breaks down naturally, giving out radiation.

What is half-life?

The time it takes for half the radioisotopes in a sample to decay.

How can radioisotopes be used to check for leaks in pipes?

By adding radioisotopes to the fluid in the pipe and using a Geiger counter to detect radiation outside the pipe.

How are radioisotopes used to treat cancer?

The gamma rays in radiation kill cancer cells more readily than healthy cells in radiotherapy.

Why are gamma rays used to sterilize medical equipment and treat food?

They kill germs and bacteria.

What are electron shells?

Arrangements of electrons around the nucleus at different energy levels.

What is the trend of the period number in the Periodic Table?

Tells you how many electron shells there are.

What is the trend of the group number in the Periodic Table?

The same as the number of electrons in the outermost shell of the participating atoms as well as valency electrons, except for Group 0.

What makes Group 0 elements unreactive?

They have a very stable arrangement of electrons (8 in the outer shell, except for helium which has 2).