Apositive charge means: a. surplus of electrons b. lack of electrons c. excess atoms d. gained protons

A positive charge means lack of electrons.

Explanation:

Atoms that are present in all bodies, are composed of electrons, protons and neutrons. All three have mass, but only the electron and the proton have charge. The electron has a negative charge, and the proton has a positive charge.

In a neutral atom, the number of protons coincides with the amount of electrons. But it may happen that these amounts are different.

When there are excess electrons, as these have a negative charge, the charge of the element will be negative. Then an anion is formed.

However, when there is a lack of electrons, the element's charge will be positive. Then a cation is formed.

So, a positive charge means lack of electrons.

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.