Answer:
A
Explanation:
an element contains only one kind of particle
Answer: 8
Explanation: Radon has 8 valence electrons. Radon is considered stable with a complete octet of electrons, filling the s and p orbitals.
The answer is/6-(1-2)
Explain why it is not that because it shown
Its C
a catalyst speeds up a reaction by offering the reaction an alternative reaction pathway with a lower activation energy
hope that helps