Apply the famous einteins equation....E=mc^2
Answer: 68.
Explanation:
The atomic number is the number that idenfities an element.
The atomic number is the number of protons of an element.
Every element has a different number of protons.
The elements are arranged in the periodic table as per their atomic number (number of protons).
The first element is hydrogen (H), its atomic number is 1, and it has 1 proton.
The second element is helium (He), its atomic number is 2 (it has 2 protons)-
Those two elements form the first period (row) of the periodic table.
The second row (period) has the elements Li, Be, B, C, N, O, F and Ne, whose respective atomic numbers (number of protons are) 3, 4, 5, 6, 7, 8, 9, and 10, respectively.
And so, you may idenfity each of the 118 elements known, with a different atomic number (number of protons).
I believe it would be the first option. It forms iron oxide (rust) when exposed to moisture and air.
D for sure hope this helps
Answer:
alkali metals
Explanation:
they all react vigorously or even explosively with cold water, resulting in the displacement of hydrogen.