What is the difference between valence and core electrons

Which of these elements had two valence electrons? hydrogen barium nitrogen Krypton bromine

What is a disadvantage of using a space-filling model to show a chemical compound?

a chemist determined by measurements that 0.0800 moles of calcium sulfide participate in a chemical reaction. Calculate the mass of calcium sulfide that participates.

This is how fluorine appears in the periodic table. 9 F Flourine 19.00 What information does "9" give about an atom of fluorine?

A 6.0 L sample of nitrogen gas contains 0.50 mole of a gas. If enough gas is added to make a total of 0.75 moles at the same pressure and temperature, what is the resulting total volume of the gas? 2.3 L 4.8 L 7.5 L 9.0 L

When magnesium combines with oxygen, the reaction involves a. a conversion of protons into electrons. b. sharing of electrons between Mg and O. c. transfer of electrons from Mg to O. d. transfer of electrons from O to Mg.

The activation energy for the reaction no2 (g) + co (g) ⟶no (g) + co2 (g) is ea = 100 kj/mol and the change in enthalpy for the reaction is δh = - 375 kj/mol.

What process transform solar energy into chemical energy?

When the reaction was carried out the calculated theoretical yield for water was 176 grams but the measured yield was 148 grams what is the percent yield

For an atom's electrons, how many energy sublevels are present in the principal energy level n = 4?