Answer:
the mass number
Explanation:
Isotopes are numerous forms of one single element. In simple terms, atomic weights are different for the isotopes. Isotopes refer to the atoms that have the same number of protons but different neutron numbers. The physical properties of the isotopes vary because these properties also based on mass. These variations can be used to distinguish isotopes of an element from each other by applying methods such as fractional distillation and diffusion.
Answer:
Oxide of M is
and sulfate of 
Explanation:
0.303 L of molecular hydrogen gas measured at 17°C and 741 mmHg.
Let moles of hydrogen gas be n.
Temperature of the gas ,T= 17°C =290 K
Pressure of the gas ,P= 741 mmHg= 0.9633 atm
Volume occupied by gas , V = 0.303 L
Using an ideal gas equation:


Moles of hydrogen gas produced = 0.01225 mol

Moles of metal =
So, 8.3333 mol of metal M gives 0.01225 mol of hydrogen gas.

x = 2.9 ≈ 3


Formulas for the oxide and sulfate of M will be:
Oxide of M is
and sulfate of
.
Water
Water is a compound because it is made from more than one kind of element (oxygen and hydrogen).
Answer:
15 protons
Explanation:
The atomic number always equals the number of protons inside the nucleus, so if the atomic number is 15, that means 15 protons are present.