McMurry (Kap.2.1)

Question 1

Which kinds of chemical bonds exist besides (covalent bonds and ionic bonds?)

Answer 1

Covalent and ionic bonds are there two extreme sides of the spectrum.

C-C = covalent
Na+ with Cl- = ionic

The bonds that are neither covalent nor ionic are named “polar covalent bonds” because they bind to each other covalently, but one atom pull the electrons to itself better then the other atom.

Question 2

What are bond polarity caused by?

Answer 2

The Electronegative difference between two atoms.

(the ability of an atom to attract the shared electrons in a covalent bond).

Question 3

Which direction do you have to go in the periodic table for the EN to grow?

Answer 3

EN grows from left to right, and from the bottom to the top.

Question 4

Why does the EN grow in that direction of the periodic table?

Answer 4

Because the proton number increase (with the number of increased electrons), which makes the nucleus positive, thereby the nucleus becomes more positive and attract the electrons in a covalent bond better.

The EN decrease when going down in a periodic table, because the number of shells increase, which “screens” the positive nucleus from attracting electrons.

Question 5

What are the EN difference measures to categorize the bonds in a (covalent, polar covalent, and ionic?)

Answer 5

Covalent (EN difference) = less then 0,5

Polar covalent (EN difference) = 0,2-2

Ionic (EN difference) = more then 2.

Question 6

How are the direction of bond polarity illustrated?

Answer 6

In a polar covalent bond, the more EN atom bears the partial negative charge, and the other atom bears the partial positive charge.

A crossed arow represent the direction of the polarity, with the tail of the arrow showing the partial positive atom and the head of the arrow showing the partial negative atom (the direction is going towards the partial negative arrow).

Question 7

What is an electrostatic potential map?

Answer 7

Charge distributions in a molecule can be displayed visually by color.

Electron rich (red), and electron poor (blue).

Question 8

How do you describe an inductive effect?

Answer 8

An atoms ability to polarize a bond. It is the shifting of electrons in a (sigma) bond in response to the electronegativity of nearby atoms.

Question 9

What does inductively donate and inductively withdraw mean?

Answer 9

Metals (lithium and magnesium) inductively donate electrons.

Reactive, non metals (oxygen, nitrogen) inductively withdraw electrons.

Plays a big role in chemical reactivity.