Covalent Bonding Flashcards Preview

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Flashcards in Covalent Bonding Deck (15):
1

What is covalent bonding ?

Is the sharing of electrons between atoms .Occurs in non-metals where electrons are shared between atoms .This is known as covalent bonding .

2

How is a covalent bond formed ?

Its formed when an electron is shared between atoms and come from the top of the energy level of atom and electrons .

3

Carbon dioxide

They are held together by weaker intermolecular forces between the molecules .Water molecular are held together by weak intermolecular forces between molecules

4

What can single covalent bonds be represented by ?

By dot and cross models showing outer shells .

5

Why does covalent bond occur ?

This is because of less energy is required to share electrons than needed for theses atoms to form ions .

6

What is dative covalent bonding ?

This is a type of covalent bond where both of shared electrons come from the same atom .Dative covalent bonds are exactly the same in lengths' /strengths as other covalent bonds .

The only difference is that shared pair of electrons come form same atom .

Look at the diagrams

7

What is bond length ?

its the average distance between the nuclei atoms in a molecule

8

What is the bond energy ?

This is the energy needed to break a bond .

9

What is bond length determined by ?

Its determined by the energy of interaction between atoms changes with distance between nuclei .

10

What do single bonds have ?

They have a greater length than double bonds and double bonds have a greater length than the triple bonds

11

What about the short length ?

The shorter length of the bond the stronger the bonds is therefore triple bond a stronger than double or single bonds .A single bond between carbon atoms has a length of 154 pm and a bond energy of 347 kj mo1 -1 .



12

Double bond between carbon atoms

has a length of 134 pm and bond energy of 612 kJ mo1 -1 .





13

Triple bond between atoms

Bond length of 120 pm and a bond energy of 820kJ mo1-1

14

An example of dative BOND

An ammonium ions contains a dative bond .When an ammonia reacts with hydrochloric acid , a hydrogen ion from the acid is transferred to the ammonium molecule .A lone pair of electrons on the nitrogen atoms forms a dative covalent bond with the hydrogen ion .


15

Why are triple lengths shorter than single or double ?

In double and triple bonds, more electron density piles up in the region between the nuclei, so the nuclei are drawn together even more closely by their attraction to the electron density.