Which alkaline earth metal most resembles
copper when analysed using a flame test?
A flame test produces a colour depending
on the ion. The alkaline earth metals are otherwise
known as group two on the periodic table. The elements in group two are beryllium,
magnesium, calcium, strontium, barium, and radium. Radium is rare and radioactive, so for
the purposes of this question, we can ignore it.
Each of these elements tends to form ions
with a two plus charge. To answer this question, we need to
recall what colour flame copper produces in a flame test and compare it to those of
beryllium, magnesium, calcium, strontium, and barium. Depending on the compound of copper will
produce a blue-green flame. Beryllium and magnesium have no
characteristic flame test colour. Calcium ions turn flames orange-red. Strontium ions turn them bright red. And the flame test colour for barium ions
The closest colour of these to blue-green
is the green of barium. So, the alkaline earth metal whose flame
test colour most resembles that of copper is barium.