Which of the following is/are true? A in each period the atomic numbers increase from
left to right
b The periods are numbered 1 through 7 on the left-
hand side of the periodic table
C Elements in the same period have chemical
properties which are not all similar
d All of the above

Answer is D. All of the above

answer

fusion: the energy source of stars. the energy released from the collapse of the gas into a protostar causes the center of the protostar to become extremely hot. when the core is hot enough, nuclear fusion commences. fusion is the process where two hydrogen atoms combine to form a helium atom, releasing energy.

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