When a strontium atom loses two electrons to form an Sr2+ ion, the electrons are lost from the a. 5s orbital. c. 3d orbital.
b. 5p orbital. d. 4f orbital.

When a strontium atom loses two electrons, it becomes a(n) cation with a charge of 2+. when any neutral atom loses an electron it becomes cation that is positively charged ions and an ion gets the charge according to the number of electrons loses.

you are very welcome but I may be inaccurate.

they begin to vibrate harder causing the material that was solid to turn into a liquid i.e gallium or ice

im pretty sure its b