Which statement concerning elements is true?
1. different elements must have different numbers of isotopes.
2. different elements must have different numbers of neutrons.
3. all atoms of a given element must have the same mass number.
4. all atoms of a given element must have the same atomic number.

no, the red giant is the hottest with 2.00.000.000 degrees celsius. while the white dwarf only 25,000 degrees celsius.

the answer is c. nacl

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.