Understanding the Atom - Quiz 2

Where is majority of the mass of an atom?

The name of Rutherford's experiment was called the [blank_start]Gold Foil[blank_end] experiment which provided evidence for the existence of the [blank_start]nucleus[blank_end] of the atom.

Label the picture with the appropriate terms. Each dot only needs one term.

A proton has a mass of 1. So Hydrogen, being the first element, has a mass of 1. Chemists hypothesised, that the proton (being almost 2000 times heavier than the electron) contributed all the mass of an atom. As such, an element like helium, which has 2 protons, would be twice as heavy as a hydrogen atom. However, it was found that it was 4 times as heavy compared to hydrogen. Why is this?

Round numbers to the nearest whole number. (eg 1.5 -> 2) Magnesium has an atomic number of [blank_start]12[blank_end]. This means it has [blank_start]12[blank_end] protons. Furthermore, Magnesium is known to have an atomic mass of [blank_start]24[blank_end]. Therefore, it must have [blank_start]12[blank_end] neutrons. In order for Magnesium to have an ionic charge of +1, it must have [blank_start]11[blank_end] electrons orbiting.

An isotope is: (may be more than one correct)

Uranium has an atomic number of [blank_start]92[blank_end]. It has [blank_start]92[blank_end] protons, but has [blank_start]146[blank_end] neutrons.