Elements Answers

All atoms of the element potassium have 19 protons. One of the most stable types of potassium atoms has the mass number 39.

The model below shows a carbide ion.

Which are different forms of an element that have different numbers of neutrons?

What is the number at the end of an isotope’s name?

The chemical symbol for the element calcium is Ca. What would be the symbol representing calcium atoms that have lost two electrons?

All large radioactive atoms decay into smaller atoms by releasing alpha particles. Each alpha particle has 2 protons, 2 neutrons, and 0 electrons. The table below describes several neutral, low-mass atoms.

Which describes an atom that has fewer neutrons than protons and more electrons than protons?

Uranium is an element that is often used in nuclear power plants. Uranium atoms are very large, and the substance can be dangerous if it is not carefully contained.

What can be added to an atom to cause a nonvalence electron in the atom to temporarily become a valence electron?

The model below shows a calcium atom.