The symbol P represents the element phosphorus. This element’s atomic number is 15. How many protons and electrons are in a P–3 ion? 15 protons and 3 electrons
12 protons and 15 electrons
15 protons and 18 electrons
18 protons and 15 electrons

Nitrogen dioxide decomposes according to the reaction 2 no2(g) ⇌ 2 no(g) + o2(g) where kp = 4.48 × 10−13 at a certain temperature. if 0.70 atm of no2 is added to a container and allowed to come to equilibrium, what are the equilibrium partial pressures of no(g) and o2(g)