Is the following chemical equation balanced?

4Al + 3O2 2Al2O3

yes
no

Which element in the third period would you expect to have the larger atomic radius, sodium (na) or sulfur (s)? a. sodium, because it has a higher effective nuclear charge attracting electrons in fewer energy levels. b. sodium, because it has fewer protons attracting electrons in the same energy levels. c. sulfur, because it has more protons attracting electrons in more energy levels. d. sulfur, because it has a higher effective nuclear charge attracting electrons in the same energy levels.

How many neutrons does an element have if its atomic number is 50 and its mass number is 166

Find the missing probability in the table below a.0.10 b.40 c.0.80 d. 0.20