Answer:
The correct answer is 5s
Explanation:
Strontium atomic number = 38
Electronic configuration is 
As
orbital is valence orbital in strontium, the outer electrons exists in that orbital only.
Answer:
Sulfur: -1
Carbon: 0
Nitrogen: 0
Explanation:
The thiocyanate ion SCN- can have only two resonance structures, which are:
S - C ≡ N <--------> S = C = N
In the first structure, we have one single bond and one triple bond, in this case, the negative charge is located in the sulfur. This is because Sulfur have 6 electrons and those electrons are present in the atom, (see picture below), and counting the electron that is sharing with the Carbon, the total electrons that sulfur has is 7 (It has one more than usual). Carbon and nitrogen are already stable with 0 of formal charge, because carbon can only have 4 electrons which 1 is sharing with sulfur and the other 3 with the nitrogen, and nitrogen have 5 electrons, three sharing with carbon and the other two kept it for itself.
In the second structure, the negative charge of the sulfur is transfered to the nitrogen, meaning that it has 6 electrons the nitrogen (formal charge -1) and carbon and sulfur with 4 and 6 electrons respectively.
Between these two structures, the most stable is the first one basically because Sulfur is a better nucleophile than the Nitrogen, and can form stronger hydrogen bond in acid, giving more stable structure.
Physical change because you didn't change the chemical compound
Answer:
Energy is absorbed, and an emission line is produced.
Explanation:
Electrons are present and revolving continuously in the orbits that are present around the nucleus. The energy of electron are fixed and unable to move to other orbits due to the strong attractive force of the proton which is present in the nucleus of the atom. If the electron wants to jump from the first energy level to the second energy level, so the electron has to absorb enough energy which can overcome the attractive force of proton.
Carbon dioxide has a total of 16 valence electrons. 1. To determine the number of valence electrons of carbon dioxide (CO2), first determine the number of valence electrons of each of the elements in the molecule.
a. We have 1 carbon (C) molecule, and 2 oxygen (O) molecules.
b. The carbon molecule has 4 valence electrons and each oxygen molecule has 6 oxygen molecules.
2. Add up the valence electrons of each of the elements
4 + (2 x 6) = 16
(from C) (2 oxygen molecules, with 6 valence electrons each)
Thus, CO2 has a total of 16 valence electrons.
The number of valence electrons can be more clearly seen from the Lewis structure of the CO2 in the figure below (Source: http://chemistry.tutorvista.com/inorganic-chemistry/bonding-electrons.html). The the dots surrounding the letters represent the valence electrons.