Which gas is most effective in absorbing incoming harmful ultraviolet radiation in the earth's stratosphere before that radiation reaches earth's surface?

Ozone (O₃) gas

Explanation:

In the Earth's stratosphere, oxygen gas (O₂) is combined with atomic oxygen (O) to form ozone gas (O₃). This is very important because ozone protects the life on Earth from ultraviolet (UV) radiation from the Sun. UV radiation is high-energy radiation, and it is very dangerous for living organisms. Ozone molecule (O₃) absorbs UV radiation and it breaks down by forming O₂ and atomic oxygen (O) again. In this way, it protects the Earth from nocive radiation.

multiplying and dividing the two decimals and the eqations by the same number of the overalls

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.