Which element will become an ion with a +2 charge

Which atom or ion is the largest? 0 a. 0 0 0 0 e. li

Oil rich countries in the middle east cover about 4% of earths total land area but prossess about 48% of the worlds known oil reserves what is the main reason for high concentration of reserves in this part of the world

Why is it incorrect to balance a chemical equation by changing the subscripts? explain.