Chapter 5 Electrons And Bonding Flashcards
What is the definition of electron configuration?
A shorthand representation that shows how electrons occupy sub-shells in an atom
What is an orbital?
A region of space in an atom around a nucleus that can hold up to 2 electrons with opposite spin
What is a sub-shell?
A group of orbitals of same type within a shell
What is a shell?
A group of atomic orbitals with the same principal quantum number,n, also known as the main energy level
What are the different sub shells?
The S- sub shell in the first shell; the S and P- sub shell in the second shell; the S,P and D-sub shell in the third shell and the S,P,D and F-sub shell in the fourth shell.
What the 3D shape of an s-orbital?
Spherical
What is the 3D shape of a P-orbital?
Dumbbell
What are the different orbitals in a P-sub shell?
In a P-orbital there are three different orbitals (x,y,z)
Z orbital- dumbbell vertical, X-orbital- dumbbell horizontal and Y orbitals- dumbbell diagonal
How many orbitals make up the D-sub shell and how many electrons can it hold?
There are 5 orbitals that make up a d-orbital therefore it can hold up to 10 electrons
How many orbitals make up the F-sub shell and how many electrons can it hold?
There are 7 f-orbitals that make up the f-sub shell therefore it can hold up to 14 electrons.
State how many electrons there can be in the first, second, third and fourth shell?
First- 2 electrons, Second- 8 electrons, Third- 18 electrons and Fourth- 32 electrons
What is the correct order of sub shells?
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 4f….
What are the exceptions to Chromium and Copper?
In order to achieve a stable arrangement of lower energy, one of the 4s electrons is promoted into the 3d sub shell. Therefore, creating a lower repulsion.
How can shorthand electron configurations be written?
Electron configurations can be expressed more simply by using the previous noble gas in the periodic table and then adding on the outer electron shells.
Where are the s,p,d and f blocks found on the periodic table?
S-block: Left block consisting of two groups
P-block: Right block consisting of six groups
D-block: Centre block consisting of ten groups
F-block: Found at the bottom of the periodic table
What is the electron configuration of ions in the s or p-block?
When forming these ions, the highest energy level loses or gains electrons
How is the electron configuration of ions from d-block elements made?
Because the 4s sub shell is at a lower energy (electrons always fill from the lower energy levels first) than the 3d sub shell, this means that the 4s sub shell fills before the 3d sub shell consequently this means that the 4s sub shell also empties before the 3d sub shell.
What is the definition of ionic bonding?
The electrostatic attraction between oppositely charged ions
What is the structure of ionic compounds?
When oppositely charged ions attract, they do so in all directions. This leads to the formation of a giant ionic lattice.
What are the properties of ionic compounds?
Melting and boiling point- takes a large amount of energy to overcome all the strong electrostatic forces of attraction between oppositely charged ions that acts in all directions within a giant ionic lattice. Therefore, Ionic compounds have high melting and boiling points.
Solubility- Many ionic compounds dissolve in polar solvents like water. In a water molecule, the oxygen atom is slightly negative and the hydrogen atom is slightly positive. When an ionic compound is placed in water, oxygen atoms of the water molecule attract to the positive ions of the compound, while the hydrogen atom attracts to the negative ion of the compound. If these attractive forces are stronger than the attractive forces between the ions, the compounds dissolve.
Electrical conductivity- In a solid state, ionic compounds dont conduct electricity because the ions are fixed in a giant ionic lattice by strong electrostatic forces of attraction and therefore can’t move . However, when molten or in aqueous states, ionic compounds are able to conduct electricity because ions are able to move.
What makes an ionic bond strong?
The strength of an ionic bond increases as the size of the ion decreases or the charge of the ion increases.
What is the definition of covalent bonding?
A strong bond between two atoms due to the electrostatic attraction between a shared pair of electrons and the atomic nuclei.
Or
A shared pair of electrons
What is dative covalent bonding?
A shared pair of electrons which has been provided by one of the atoms only (the donor)
What is the process of dative covalent bonding?
The electrons of the shared pair are provided by one species (donor) and it shares the electrons with the acceptor. Donor species will have lone pairs in their outer shells, while acceptor species will be short of their ‘octet’ or maximum.
What is the dative covalent bond of ammonia?
—— —— +
| H |
| | |
| H— N —>H |
| | |
| H |
——— ——-
Explain SF6
Sulfure hexafluoride is able to expand the octet rule and contain 12 electrons in the outer shell as it has available orbitals to accommodate more electrons.
Explain Bf3
Boron trifluoride can contain less than the maximum octet as it is stable due to the central atom maximising the number of possible covalent bond pairs.
How are simple molecules structured?
Simple molecules contain only a few atoms held together by covalent bonds, however each molecule is attracted to other neighbouring molecules by weak intermolecular forces which hold them together.
What are the properties of simple molecules?
Low Boiling Point- Intermolecular forces are easily overcome and broken
Don’t conduct electricity- There are no mobile charge carriers (ions and electrons)
How is Diamond structured?
In a giant covalent structure/lattice as each carbon atom forms 4 bonds with 4 other carbon atoms, forming a giant network.
What are the properties of Diamond?
Very high melting point- Network of strong covalent bonds which take a lot of energy to be broken.
Doesn’t conduct electricity- no free mobile charge carriers
What other giant covalent structure has the same properties as Diamond?
Silicon trioxide (sand)
How is Graphite structured?
This is an allotrope of carbon as each carbon atom forms 3 bonds with 3 other carbon atoms leaving a delocalised electron for each carbon atom which is free to move between the layers. There is an attraction between the layers of carbon atoms and the delocalised electrons.
What are the properties of Graphite?
Soft and slippery- the layers of the carbon atoms can slide over each other
High melting point- a large amount of energy is required to overcome the covalent bonds
Conducts electricity- delocalised electrons that can move throughout the structure
What is the average bond enthalpy?
Serves as a measurement of covalent bond strength. The larger the value of the average bond, the stronger the covalent bond.
What are the properties of monatomic substances?
Low melting and boiling points because there are weak forces in between the atoms which means that little energy is required to break the bonds.
Insoluble
Does not conduct electricity because there are no free mobile charge carriers
Explain why giant covalent substances have high melting and boiling points
Giant covalent structures have high melting and boiling points due to the strong network of covalent bonds which requires a lot of energy to overcome.
Explain why it would be incorrect to describe Na2O as a “molecule”?
Because the substance is a compound made up of positively and negatively charged ions
Why are covalently bonded substances insoluble?
They have a non polar structure and therefore can only dissolve in non polar solvents
Describe and explain the electrical conductivity of sodium in its solid and molten states
Sodium conducts electricity in solid and molten states as it contains delocalised electrons in both states,
Describe what is meant by the terms ionic lattice, in terms of arrangement and particles present?
Regular repeating arrangement of oppositely charged ions that acts in all directions due to the electrostatic attraction.
