Electron Configuration

How do you write shorthand electron configuration?

Used a bracketed noble gas symbol to represent the configuration of the noble gas from the preceding row

What is an electron shell diagram used to show?

Used to show how many electrons are in each energy level

What are the irregular electron configurations?

-Chromium (steals a 4s electron to half fill its 3d sublevel) -Copper (steals a 4s electron to fill its 3d sublevel)

How do you create a shell diagram?

-Count the total number of electrons in each energy level and write that number in the shell -Be sure to fill the energy levels in the correct order

How do shell diagrams work?

-Electrons are arranged around the nucleus in shells (principal energy levels). The shells are number outward from the nucleus -The maximum number of electrons found in each shell can be calculated by: "2n^2" where "n" is the number of shells

What is Hund's Rule?

-Electrons occupy energy levels so that a maximum number of unpaired electrons result (Every orbital gets 1 electron first. Then go back and pair up) <- Minimizes repulsion between electrons -AKA "Urinal Theory of Electrons"

What are cations?

-Lost electron, become +

What happens as you move down the periodic table?

-More shells, thus larger atomic radius -More core electrons, thus more shielding, thus less nuclear attraction, and also a larger atom

What is the Aufbau Principle?

-Orbitals fill in a certain order -Electrons are added one at a time to the lowest energy level orbitals available until all the electrons of the atom have been accounted for -Total number of electrons in a neutral element is equal to the atomic number

How difficult is it to remove a valence electron at different positions on the periodic table?

-Related to atomic radius -Down the periodic table: Easier to remove valence electrons -At the top of the periodic table: Harder to remove valence electrons -As you move right, the more valence electrons you add, the closer the the element is to fulfilling its ocelot, thus the harder

What is the diagonal rule?

-The diagonal rule is a memory device to remember the order of filling -Start at the 1s orbital and then follow the arrows -Remember that s orbitals can hold 2 electrons, p orbitals 6 electrons, d orbitals 10 electrons, and f orbitals 14 electrons

When are shell diagrams used and what do they show?

-They are used when you don't need to see exactly which orbitals all the electrons are in you create a shell diagram -Shell diagrams show the total number of electrons in each principal energy level

LOOK AT PROBLEMS ON POWERPOINT

1-5 PROBLEMS AT THE END OF POWERPOINT 2

Example: What is the electron configuration for N?

1s2, 2s2, 2p3

Example: What is the electron configuration for S?

1s2, 2s2, 2p6, 3s2, 3p4

Example: What is the electron configuration for Ar?

1s2, 2s2, 2p6, 3s2, 3p6

Example: What is the electron configuration for Au?

1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2, 4f14, 5d9 (actual e-config: ...6s1, 5d10)

Example: What is the electron configuration for Fe?

1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d6

What is the Pauli Exclusion Principle?

An orbital can hold a maximum of 2 electrons and to occupy the same orbital, the 2 electrons must spin in opposite directions

What electrons act as core electrons?

Any electrons that are NOT the valence electrons will act as the core electrons (inner electrons)

What happens as you move across the periodic table?

As you move to the right, the number of valence electrons and protons increases -This increases the nuclear attraction. More attraction = nuclear pulling the valence electrons inward = smaller atom

Why are there trends/patterns found throughout the periodic table?

Because the periodic table is arranged through electron configuration -Block (s,p,d or f) = type of orbital being filled -Column # in block = number of electrons in sub level being filled

What is electron repulsion?

Because valence electrons are negatively charged, pairs of electrons tend to repel from one another

Do atoms get bigger or smaller as you move down a group?

Bigger; More energy levels, larger energy levels

What is the easiest way to create a shell diagram?

By using an atom's electron configuration

What does the number and arrangement of core and valence electrons determine?

Determines each atom's physical and chemical properties

What are core electrons?

Electrons that are located in energy levels between the nucleus and the valence shell

What are valence electrons?

Electrons that are located in the outermost occupied energy level of an atom ("valence shell"

What is 1st Ionization Energy?

Energy required to remove an atom's most loosely held valence electrons? -IE increases as you move up a group -IE increases as you move right across a period

What are anions?

Gained electron, become - -Larger than their parent atoms because they gained an electron (may add energy levels)

Does electronegativity increase or decrease as you move up a group?

Increase -Fewer energy levels so shared electrons are closer to the + nucleaus -> stronger pull

Does electronegativity increase or decrease as you move right across a period?

Increase -Nuclear charge increase as you move right, thus stronger attraction for shared electrons

What does it mean if the orbitals are "fuzzy"?

It means they are not defined

What happens as an orbital's principle energy level increase?

It's size and the amount of energy an electron must have to exist increases

Are there defined atomic orbitals?

No, there are no defined orbits, as in circular pathways

Describe orbitals and name what they are labeled

Orbitals have various sizes and shapes. They are labeled s, p, d, and f

What are "orbitals"?

Regions in space around the nucleus where electrons with a certain energy level are most likely to be found?

What are the rules for orbital diagrams?

Rule #1: Start closest to the nucleus. Add electrons to sub levels in order of increased energy until you run out. Rule #2: Every orbital gets 1 electron first. Then go back and pair up NOTE: Max 2 electrons per box and used up and down arrows to show opposite spins. Also remember the different heights the boxes are at

What are the max electrons in each shell that you can have?

Shell 1: 2 Shell 2: 8 Shell 3: 18 Shell 4: 32 Shell 5: 50

Do atoms get bigger or smaller as you move right across a period?

Smaller; increasing number of protons -> stronger nuclear charge -> valence electrons pulled closer to the nucleus -> atoms get smaller

What is nuclear attraction?

The attraction between the nucleus (positively charged) and the valence electrons (negatively charged) -also called outer electrons. The more protons in the nucleus, the stronger the pull

What increases as the number of electrons an atom has increases?

The number of orbitals

How are orbitals laid over each other?

The orbitals lay over each other in 3D with the nucleus at the cenete

What is the atomic radius?

The size of the atom (distance between the nucleus and the valence electrons)

What is ionic radius?

The size of the ion

What is electronegativity?

The tendency or how likely it is to pull a valence electron (take away -The ability of an atom involved in a chemical bond to pull shared electrons towards itself

How do you write electron configuration?

Use the orbital diagram to count the number of electrons in each energy sub level and orbital. Then write that number as a superscript on the energy level/orbital type -The sum of all subscripts in the electron configuration must equal the total number of electrons in the atom

What is an orbital diagram used to show?

Used to show how many electrons are in each orbital by energy level

What is electron configuration used to show?

Used to show how many electrons are in each orbital energy level

What is electron shielding?

When the core electrons shield or block some of the nuclear attraction. The more core electrons, the more shielding, thus less nuclear attraction

Things to remember for electron configuration

Write the electron configuration in order of increasing energy and don't forget that each sub level has a maximum electron capacity -s=2; p=6; d=10; f=14

Example: What is the shorthand electron configuration for sodium (11e-)?

[Ne] 3s1

What is the shorthand electron configuration for sulfur (16e-)?

[Ne] 3s2, 3p4