Answer: Equal number of protons and electrons. Example: an atom of oxygen atom has 8 electrons and 8 protons and is neutral.
Explanation:
An atom that has no charge is a neutral atom. It contains electrons equal to protons. For example: A neutral atom of oxygen has 8 protons and 8 electrons.
An atom which has charge is said be ionized. It is either positively charged or negatively charged. It is positively charge when the number of electrons is less than the number of protons. For example: 
contains 10 electrons and 11 protons.
And when the number of electrons is greater than the number of protons, the atom is negatively charged. For example, 
has 17 protons and 18 electrons. It readily accepts an electron to complete its octet.
Answer:
The magnetic field of Earth is created by currents of electricity that flow in the molten center.
Explanation:
Answer:
Straight line in the direction of the tangential velocity the ball had at the moment the string broke
Explanation:
After the string breaks, the ball now disconnected from the centripetal force that was exerted via the string, continues its travel in a straight line in the direction of the tangential velocity it had at the moment the string broke.
The bus is going forward and suddenly stops
