<u>Answer:</u> The correct answer is positive ions, by losing electrons to empty the valence shell.
<u>Explanation:</u>
Metals are defined as the elements which loose electrons to attain stable electronic configurations. If an element looses an electron, it will have more number of protons and thus will carry a positive charge on it.
Examples of metals are Sodium (Na), Calcium (Ca) etc.
Sodium metal has atomic number of 11 and electronic configuration of . As, this element will loose 1 electron and thus will form ion.
Calcium metal has atomic number of 20 and electronic configuration of . As, this element will loose 2 electrons and thus will form ion.
Hence, the correct answer is positive ions, by losing electrons to empty the valence shell.