How many protons, neutrons and electrons are there in a neutral atom of magnesium-25? [protons], [neutrons], [electrons] 

What is the mass number of an atom that contains 26 protons, 29 neutrons, and 26 electrons? [massnumber] What is the symbol for the element? [symbol]

Classify the following as either a pure substance, a homogeneous mixture or a heterogeneous mixture: apple juice

Classify the following as a chemical or physical change: melting wax

Classify the following as either a pure substance, a homogeneous mixture or a heterogeneous mixture: baking soda, NaHCO3

Classify the following as a physical or chemical property: The colorless gas hydrogen, reacts explosively when ignited in air.

After the age of 65, the recommended daily intake of calcium is 1500 mg. If a person takes in 975 mg/day, what percent of the recommended daily intake is the person receiving?

What would you multiply moles of fluorine (F) by to get the units atoms of fluorine? 

How many protons, neutrons and electrons are there in an atom that has an atomic number of 81 and a mass number of 209? [protons], [neutrons], [electrons] What is the symbol for the element? [symbol]

Which of the following correctly classifies this substance, CO?