6.02x10^23; This represents the number of molecules in 1 mole of a substance.
Answer:
There are two sets of groups in the periodic table. The first set are Group A elements and are also known as representative elements. The second set are Group B elements and are also known as transition metals. Representative elements are the most abundant elements on earth.
B. At-200
In beta decay the atomic number increases by 1
Alpha particles because two protons and two neutrons