Please Help D: Which of the following elements has the smallest atomic radius?
A [Ar] 4s^2
B [Ar] 3d^10 4s^2
C [Ne] 3s^1
D [Ar] 4s^1

Which of the following did jj thompson discover about atoms? a)an atom has an internal structure. b) atoms are tiny indivisible particles. c)electrons orbit the nucleus of an atom. d) the nucleus of an atom contains protons and neutrons.

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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.