B. Isotopes have different numbers of neutrons but the same number of protons.
Nitrogen is a non-metal and aluminum is a metal so the bond would be ionic.
i will ans the 2nd part first:
heat sources 4 homes: those wuld be renewable resources that generate heat. They include geothermal, solar water-heating and bio-mass.
primarily produce electricity: those wuld be something that is big like a dam for hydroelectric, wind turbine for electric generation, and solar farm for electricity.
The solid compound, K2SO4 contains a cation called K+ and an anion called SO42-. In this case, there are 2 atoms of potassium, 1 atom of sulfur and 4 moles of oxygen. The compound also contains ionic bonds because of the composing non-metals and metal.
