It would be to see your awnsers
Dmitri Mendeleev is the scientist who first developed the periodic table.
He is a Russian chemist and inventor who formulated the periodic law and created the periodic table of elements. He corrected some of the properties of the elements. Now, we can easily locate the elements we wanted to identify. With the help of Mendeleev, studying chemistry is not that difficult because he tried to simplify some of the concept that was complex before.
As the air molecules move through the valve they have friction as they hit the walls, and its this friction that causes it to heat up.
A burning fossil fuels that produces energy
I think the answer is (1) Co. Because the element of Cobalt also has 2 electrons at the outer layer which is the same as Calcium. And the outer layer is an important factor which can affect the property of an element.
