1s 2s22p63s23p4
How many valence electrons does this atom have?
2
6
4
12

Why are the trends and exceptions to the trends in ionization energy observed?

Once similarity and one difference between a mixture of elements and a mixture of compounds

Consider the reaction: 2al(s) + fe2o3(s) → al2o3(s) + 2fe(s) the δhf for fe2o3(s) = -824.3 kj/mole. the δhf for al2o3(s) = -1675.7 kj/mole. finish the equation. δhrxn = [(1)( kj/mole) + (2)( kj/mole)] - [(1)( kj/mole) + (2) ( kj/mole)]