D water expands when it freezes
Answer: If the outermost shell has 1–4 electrons, it is a metal.
If the outermost shell has 5–7 electrons, it is a non-metal.
In ions atoms lose and gain electrons
Answer:
Why some elements are radioactive (unstable). When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced or unstable. Whether radioactive elements can become stable and if so, how. The unstable nucleus of radioactive atoms emit radiation.
Explanation:
hope this helps
Answer:
elements in same group have same valence electron.
period of element is equal to valence shell
Explanation:
if the elements are in a same group then they will be having same number of valence electron.
the period of an element in periodic table is equal to the valence shell of the element. that is if the valence electron are in 3 rd shell then the element will be in third period.
