Which of these pairs of elements have the same number of valence electrons

phosphorus (P) and chlorine (Cl)

beryllium (Be) and calcium (Ca)

chlorine (Cl) and helium (He)

oxygen (O) and carbon (C)

What happens when an atom has more electrons than can fit in one energy level?

What occurs when the products have less enthalpy than the reactants?

The atomic number of the sodium atom is 11. The atomic mass number can be estimated by rounding the atomic mass to 23.

How much energy is evolved during the formation of 98.7 g of Fe, according to the reaction below? Fe2O3 (s) + 2 Al (s) → Al2O3 (s) + 2 Fe (s) ΔH°rxn = - 852 kJ How much energy is evolved during the formation of 98.

Why do planets in our solar system stay in their position? A. friction B. they travel the same distance from each other C. the suns radiation keeps them there D. the suns gravity keeps them in place

What is the total number of atoms in this formula? NaHCO3

An object was measured by a worker as 14.6 cm long, however, the manufacturer specifications list the length of the object at 14.4 cm. What is the percent error in the workers measurement

Does The human brain retains more information than all the books in the Library of Congress

Will an object with a density of 0.97 g/ml float or sink in water

Which subatomic particle contributes least to the mass of the atom? which subatomic particle contributes least to the mass of the atom? neutron electron proton all of these contribute equally?