An atom has 23 protons, 25 neutrons and 23 electrons. what is the element symbol
what is the atomic number
what is the mass number

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

Write the chemical formula for a compound that is made of an element from group 1 and an element from group 17

A4.86 g piece of metal was placed in a graduated cylinder containing 15.5 ml of water. the water level rose to 17.3 ml. what is the density of the metal. i need the steps of how to solve it to so i can use a formula to work out other problems.