How difficult it is to change an objects motion. Think of a tablecloth; it takes energy to move it from underneath objects on the table, and it takes energy to move the objects themselves on the table.
<span>a pure substance that can be separated into different elements by chemical means</span>
Answer:
3. An oxygen atom with 8 electrons, 8 protons, and 9 neutrons .
Explanation:
if an atom contains equal numbers of protons and electrons, the atom is described as being neutral.
