The nucleus of an atom consists of protons, which have a positive electrical charge, and neutrons, which have no charge- Electrons, which have a negative charge, circle the nucleus in the orbital shell.

2Na + 211011 --* 2Na()l I - IU is a single replacement reaction where one sodium atom replaces jast one of the hydrogen atoms in each water molecule.

Volume equals length times width times height (V =lwh). In this case, V = 64, so one side of the box is 4- inches long. The cube root of 64 produces this number: 64 = 4 × 4 × 4. Find the perimeter by adding the four sides together: 4 + 4 + 4 + 4 = 16.

An object in equilibrium may or may not be at rest. If two or more forces act, their effects may eliminate each other. When this condition of equilibrium is reached, there is no net force and the velocity does not change. Equilibrium is reached when the object is at rest or moving at a constant speed and in a straight line