<u>Answer:</u> The element E is Krypton (Kr).
<u>Explanation:</u>
In a nuclear reaction, the total mass and total atomic number remains the same.
The given nuclear reaction follows:
Total mass on reactant side = total mass on product side
75 = A + 0
A = 75
Total atomic number on reactant side = total atomic number on product side
35 = Z + (-1)
Z = 36
The isotopic symbol of element E is 
Hence, the element E is Krypton (Kr).
Answer:
The correct answer is 1 and 4, thus
Testing for the presence of 1. Thymine (DNA) and 4. Uracil (RNA)
Explanation:
DNA and RNA differ in the composition of their nucleotides in that one of their four nucleotide organic bases differs in the two polymers. While bases adenine, guanine, and cytosine are present in RNA and DNA; only DNA contains thymine DNA, and only RNA contains uracil. These components, Adenine, Guanine, Thymine, Uracil and Cytosine are abbreviated as A, G, T, U, and C, respectively. Their acronyms above are used to represent long complexes formed by these bases.
Answer:
B. Group 17
Explanation:
The element is Bromine. Its electron configuration is:
1s2 2s2p6 3s2p6d10 4s2p5
You can see that its last orbital is 4p^5 for 5 electrons in the 4p orbital.
He valence of selenium depends on which compound it is in. Selenium is very similar to sulfur. It may have a valence of 6; example selenium hexafluoride SeF6, selenium trioxide SeO3
<span>4; example selenium tetrafluoride SeF4, selenium dioxide SeO2 </span>
<span>2; example selenium difluoride SeF2, selenium dichloride SeCl2 </span>
<span>and -2; example hydrogen selenide H2Se</span>
