Which of the following chemical equations refers to the SECOND ionization of Al? a. Al(s) + 2e– → Al2–(s) b. Al+(g) → Al2+(g) + e– c. Al(g) → Al2+(g) + 2e– d. Al(s) → Al+(s) + e– e. Al2+(g) + e– → Al+(g)

Consider the two electron arrangements for neutral atoms a and b. are atoms a and b the same element? a - 1s2, 2s2, 2p6, 3s1 b - 1s2, 2s2, 2p6, 5s1

How did planetesmals form planets? a. they broke apart into smaller chunks.b. they collided and stuck together.c. they cooled and pulled ice together.d. they began to rotate.

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.