Why is cobalt (Co) placed before nickel (Ni) on the periodic table of the elements even though it
has a higher average atomic mass than nickel?
A Nickel has one more proton.

B Cobalt was discovered first.

C Nickel has fewer electrons.

D Cobalt has a lower density.

Which statement best describes the flow of energy in this scenario

The table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 9 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of tthe table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 9 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

What is the percentage of hydrogen in c2h4