Answer:- b. +3
Explanations:- Charge of a metal ion is equal to the number of valence electrons it has as it loses these electrons to have its nearest noble gas like electron configuration.
Al has 3 valence electrons and being a metal it loses all of these and so the charge of Al ion is +3. It could be shown as:

So, the right choice is b. 3+.
Answer:
The main reason people perspire is that the evaporation of water can cool our bodies. ... Sweat is chemically similar to plasma, but certain components are selectively retained or excreted.
Explanation:
Answer: Thomson - C
Rutherford - B
Bohr - A
Explanation: I just took the quiz
The atomic number increases moving left to right across a period and subsequently so does the effective nuclear charge. Therefore, moving left to right across a period the nucleus has a greater pull on the outer electrons and the atomic radii decreases.
Answer:
The removal of one or more electrons from a neutral atom results in a cation.
Explanation:
When you remove electrons from a neutral atom, the atom becomes more positive. Electrons have a negative charge and the protons inside of the nucleus have a positive charge. When electrons are removed, the positive charges from the protons outweigh the negative charges. This results in a positively charged atom, called a cation.