Which of these pairs of elements have the same number of valence electrons?
hydrogen (h) and helium (he)
sodium (na) and potassium (k)
carbon (c) and oxygen (o)
boron (b) and beryllium (be)

What is the empirical formula of vanadium 1 oxide given that 20.38 grams of vandium combines with oxygen to form 23.58 grams of the oxide

Acylinder is filled with 2.00 moles of nitrogen, 3.00 moles of argon and 5.00 moles of helium. if the gas mixture is at stp, what is the partial pressure of the argon

What does a particular point on a line of a phase diagram represent? o a. the maximum temperature a substance can exist at without bonds breaking b. the pressure created by the kinetic energy of molecules at a particular temperature c. the melting point or boiling point of a substance at a specific pressure d. the conditions in which temperature and pressure have equal effects on a substance