D. respiration by plants and animals
<span>B. Electrons are scattered in an atom.
Dalton only came to the conclusion at atoms existed, not their contents. He did this by using gases and making them react and made observations about the gases.</span>
Answer:
Bohr's greatest contribution to modern physics was the atomic model. The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons.
Explanation:
Answer:
All helium atoms have two protons, and no other elements have atoms with two protons. In the case of helium, the atomic number is 2. The atomic number of an element is usually written in front of and slightly below the element's symbol, like in the Figure below for helium.