Which of these elements has two valence electrons? A. hydrogen B. barium C. nitrogen D. krypton E. bromine

1 mole of sulfur atoms has how much mass A 6.02 x 10^23g B 32 x (6.02 x 10^23) g C 32 g D 16 g

Consider a hydrogen atom in the ground state. What is the energy of its electron? which is, - 2.1799 X10^-18 J Now consider an excited-state hydrogen atom. What is the energy of electron in the n=2 level?

The carbocation electrophile in a friedel-crafts reaction can be generated in ways other than by reaction of an alkyl chloride with alcl3. give an example

a nucleus occupies a very small about of space inside an atom. from the nucleus of an atom to be a ball 10 cm in diameter.

11. What's the atomic number of lodine?

What type of energy travels in the form of electromagnetic waves?

At the same pressure, about 25 times more co2 will dissolve in plasma as o2. why does this occur?

Describe what occurs when a gas is collected by water displacement, including why a table of water vapor pressure values is needed.

The theory of plate tectonics

A sample of sodium reacts completely with 0.568 kg of chlorine, forming 936 g of sodium chloride. What mass of sodium reacted?