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# Tutor profile: Lena I.

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Lena I.
Masters Student at MGH IHP
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## Questions

### Subject:Chemistry

TutorMe
Question:

What is the order of the ionic radii of N3-, O2-, F- and Na+ follow?

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Lena I.

If we look at the charge of each atom we will see that N3- has 3 extra electrons so that means that the electrons will be less attracted to the proton in the nucleus since the electrons are more crowded thus this creates a larger radius since the electrons and protons aren’t tightly attracted. The radii will become smaller with less extra electrons. When there are less electrons than protons like in Na+ then the electrons will have a greater attraction to the protons since it isn’t as crowded creating a smaller radius and a stronger attraction. So when we arrange atom radii from largest to smallest we will look at the most negative atom to have the largest to the most positive atom to have the smallest radius. N3- > O2- > F- > Na+

### Subject:Biology

TutorMe
Question:

What are cells called that have an enclosed nucleus and what are the main parts of a nucleus?

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Lena I.

Cells that have an enclosed nucleus are called eukaryotic cells and the main elements of a nucleus are DNA molecules that make up chromatin, the nucleolus, the nucleoplasm and the nuclear membrane.

### Subject:Algebra

TutorMe
Question:

Evaluate f(2) - f(1) if f(x) = 6x + 1

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Lena I.

Given the function f(x) = 6x + 1 f(2) - f(1) is given by. f(2) - f(1) = (6*2 + 1) - (6*1 + 1) = 6

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