Physicist Albert Einstein derived an equation ( E=mc2) by the twentieth-century, in which E represents units of energy, m represents units of mass, and c2 is the speed of light squared, or multiplied by itself.
Hydrogen (H) was first, followed by helium (He).
Answer:
Okay?.......................
Explanation:
Acids and alkalis both contain ions. Acids contain lots of hydrogen ions, which have the symbol H+. Alkalis contain lots of hydroxide ions, symbol OH-. Water is neutral because the number of hydrogen ions is equal to the number of hydroxide ions