Valence electrons are the electrons in the outermost shell, or energy level, of an atom. For example, oxygen has six valence electrons, two in the 2s subshell and four in the 2p subshell. We can write the configuration of oxygen's valence electrons as 2s²2p⁴
Answer:
Adenine forms two hydrogen bonds with thymine;
guanine forms three hydrogen bonds with cytosine
Explanation:
There are three hydrogen bonds between guanine and cytosine. Between adenine and thymine, two hydrogen bonds form. Complementary pairs always include one base of purine and one base of pyrimidine.
Answer:
8.7g/mL
Explanation:
I used the density formula to solve. d=m/v= 20g/2.3mL
Answer:
5.8 moles of copper are needed to react with sulfur to produce 2.9 moles of copper (I) sulfide.
Explanation:

Moles of copper(I) sufide = 2.9 mol
According to reaction, 1 mole of copper(I) sulfide is obtained from 2 moles of copper, then 2.9 moles of copper(I) sulfide will be obtained from :
copper
5.8 moles of copper are needed to react with sulfur to produce 2.9 moles of copper (I) sulfide.
Answer:
It well melt.While theother one will dry
Explanation: