Substances have different tendencies to donate or accept electrons. When a really good donor meets a great acceptor, the chemical reaction releases a lot of energy. Oxygen (O2) is the best electron acceptor and is used in many aerobic reactions (reactions with oxygen). Hydrogen gas (H2) is a good electron donor.
When O2 and H2 are combined, along with a catalyst, water (H2O) is formed. This example of a redox reaction can be written like this:

<span>A supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.</span>
To find<span> the </span>valence electrons in an atom<span>, identify what group the element is in. An element in group 1A has 1 </span>valence electron<span>. For example, Li is in group 1A, so that means it has one </span>valence electron. If the element is in group 2A, then it has two valence electrons<span>.</span>
Covalent bonds are formed when 2 neutral atoms come together to share a pair of electrons, where each atom contributes one electron each to be shared.
The covalent bond is kept together by the electrostatic attraction between the nuclei of the atoms and the shared pair of electrons.
Covalent bonds are usually formed between non metals with a small difference in their electro negativity.
the correct answer is
A. Neutral atoms coming together to share electrons
There are 9 orbitals in the third energy level and 25 orbitals in the fifth energy level.
I hope this helps you.
