What are the electrons is the outer shell of an atom called?
what charge will elements in group 2 form when they are involved in an ionic bond?

What are the genotypic and phenotypic ratios

What is the percentage composition of carbon in the compound ch4

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?