Atoms have ...

• a very small heavy nucleus containing protons that are positively charged and uncharged neutrons.
• a cloud of light weight even smaller electrons which are negatively charged.
• lots of empty space.

Usually atoms have equal amounts of positive and negative charge making them neutral. There are equal numbers of protons and electrons so the positive and negative charges balabce out.

• If one or more electrons are added to an atom, it becomes negatively charged.
• If one or more electrons are removed from an atom, it becomes positively charged.

Here is a simplified animation of a hydrogen atom. Apologies to all quantum physicists who will know that there is rather more to atoms than this introductory view. Full Screen