Answer: A.
fossil
B.
rock layer
Explanation:
Relative aging or dating can be define as the technique for determination of the age of the rock and fossil. It is a method of determining the chronological order of the past events by comparing the stratigraphic column of rocks and sediments with each other. This method can only give relative age of one object in comparison with the other but does not give the absolute date.
Answer:
Clavulanic acid has two (2) chiral centers.
Explanation:
A chiral center is a center (usually carbon) with four different substituents.
The structure of clavulanic acid is shown in the attachment below.
Consider the labeled diagram in the attachment,
Carbon A is not a chiral carbon because it has two hydrogen atoms attached to it
Carbon B is not a chiral carbon because it has only three substituents
Carbon C is a chiral carbon because it has four different substituents
Carbon D is a chiral carbon because it has four different substituents
Carbon E is not a chiral carbon because it has only three atoms directly attached to it
Carbon F is not a chiral carbon because it has only three atoms directly attached to it
Carbon G is not a chiral carbon because it has two hydrogen atoms attached to it
Carbon H is not a chiral carbon because it has only three substituents
Then, only carbons C and D are chiral carbons.
Hence, clavulanic acid have two (2) chiral centers.
Answer:
I don't know if you can directly prove it with evidence if you haven't observed it but you can maybe take an educated guess by the aftermath of it?
For example, you see a burnt log. At this time, people don't know what fire is. After we study the log, we could see that it takes extreme temperature in order to burn the log and that would help people see that there is a force like fire that can cause this. In a way, finding out that extreme temperatures burns stuff is another step closer to the discovery and proof of fire
I hope that makes sense
Answer:
Rank in increasing order of effective nuclear charge:
Explanation:
This explains the meaning of effective nuclear charge, Zeff, how to determine it, and the calculations for a valence electron of each of the five given elements: F, Li, Be, B, and N.
<u>1) Effective nuclear charge definitions</u>
- While the total positive charge of the atom nucleus (Z) is equal to the number of protons, the electrons farther away from the nucleus experience an effective nuclear charge (Zeff) less than the total nuclear charge, due to the fact that electrons in between the nucleus and the outer electrons partially cancel the atraction from the nucleus.
- Such effect on on a valence electron is estimated as the atomic number less the number of electrons closer to the nucleus than the electron whose effective nuclear charge is being determined: Zeff = Z - S.
<u><em>2) Z eff for a F valence electron:</em></u>
- F's atomic number: Z = 9
- Total number of electrons: 9 (same numer of protons)
- Period: 17 (search in the periodic table or do the electron configuration)
- Number of valence electrons: 7 (equal to the last digit of the period's number)
- Number of electrons closer to the nucleus than a valence electron: S = 9 - 7 = 2
- Zeff = Z - S = 9 - 2 = 7
<u><em>3) Z eff for a Li valence eletron:</em></u>
- Li's atomic number: Z = 3
- Total number of electrons: 3 (same number of protons)
- Period: 1 (search on the periodic table or do the electron configuration)
- Number of valence electrons: 1 (equal to the last digit of the period's number)
- Number of electrons closer to the nucleus than a valence electron: S = 3 - 1 = 2
- Z eff = Z - S = 3 - 2 = 1.
<em>4) Z eff for a Be valence eletron:</em>
- Be's atomic number: Z = 4
- Total number of electrons: 4 (same number of protons)
- Period: 2 (search on the periodic table or do the electron configuration)
- Number of valence electrons: 2 (equal to the last digit of the period's number)
- Number of electrons closer to the nucleus than a valence electron: S = 4 - 2 = 2
- Z eff = Z - S = 4 - 2 = 2
<u><em>5) Z eff for a B valence eletron:</em></u>
- B's atomic number: Z = 5
- Total number of electrons: 5 (same number of protons)
- Period: 13 (search on the periodic table or do the electron configuration)
- Number of valence electrons: 3 (equal to the last digit of the period's number)
- Number of electrons closer to the nucleus than a valence electron: S = 5 - 3 = 2
- Z eff = Z - S = 5 - 2 = 3
<u><em>6) Z eff for a N valence eletron:</em></u>
- N's atomic number: Z = 7
- Total number of electrons: 7 (same number of protons)
- Period: 15 (search on the periodic table or do the electron configuration)
- Number of valence electrons: 5 (equal to the last digit of the period's number)
- Number of electrons closer to the nucleus than a valence electron: S = 7 - 5 = 2
- Z eff = Z - S = 7 - 2 = 5
<u><em>7) Summary (order):</em></u>
Atom Zeff for a valence electron
- <u>Conclusion</u>: the order is Li < Be < B < N < F
C. rusting is the correct answer
