Which statements about a phosphorus atom, P, are correct? 1. The nucleon number is 16.
2. The number of outer electrons is 5.
3. The proton number is 15.

3. The proton number is 15.

Explanation:

Phosphorus, P is the element with the atomic number = 15. The atomic number = Number of protons. That means:

3. The proton number is 15.

Now, the number of protons = Number of electrons = 15.

And, nucleon number = Number of protons + number of neutrons. The must abundant phosphorus atom contains 16 neutrons and nucleon number is: 15+16 = 31.

Thus, we can know which statement is true.

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

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explanation: