This is how sodium appears in the periodic table.

Question

An orange box has N a at the center and 11 above. Below it says sodium and below that 22.99. A blue arrow points to 22.99.

The arrow is pointing to sodium’s

number of neutrons.
chemical symbol
atomic mass
combined number of electrons and protons.

Answer 1

The arrow is pointing to sodium’s atomic mass.

In the periodic table, the number at the bottom (22.99 in this case) represents the atomic mass of the element. The atomic number (11 above) indicates the number of protons (and also electrons in a neutral atom) in sodium. The number of neutrons can be calculated by subtracting the atomic number from the atomic mass (rounded to the nearest whole number).