Ba 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s² → [Xe]6s²
Ba - 2e⁻ → Ba⁺² [Xe]
Here are the list of nucleo bases : adenine , Thymine, Guanine , Cytosine
Adenine pairs with Thymine, and Guanine pairs with Cytosine
Adenine + Guanine = Purine
Thymine + Cytosine = Pyrimidine
So the answer for number 1 will be : Purine, since Adenine is not the choice
And the answer for number 2 is Guanine
hope this helps
Answer:
Explanation:
Specifically, what do we mean when we say that a scientific hypothesis must be testable? It must be able to be proven wrong. ... A scientific fact is something that observers can observe and agree to be true. A hypothesis is an educated guess that answers a question.
The correct answer is D:
it involves breaking molecular bonds between copper compounds
.
The explanation :
-when we melt a copper it is a physical change because the substance is still copper and have the same shape.
- but for example Burning a copper it is a chemical change. Fire activates a chemical reaction between copper and oxygen.
-The oxygen in the air reacts with the copper and the chemical bonds are broken.
- the chemical change is changing the other compound bonded to the copper atoms.
So, the correct answer is D
