Location of Electrons

Location of Electrons

Based on current models... where can we find electrons?

Bohr Model of the atom

• Though the Bohr model is not entirely correct it is useful for discussing electron location.

Bohr Model of the atom

• Something that changed between Rutherford and Bohr's models is the idea, that Bohr proved mathematically, that electrons can only orbit an atom at certain energy levels also known as electron shells.

Bohr Model of the atom

• These separate energy levels are represented in the diagram on the left as circles around the nucleus. With the n= telling us of the different energy levels.

Bohr Model of the atom

• Electrons can only be found at these energy levels, also known as electron shells.

• You would not find an electron in between electron shells.

Multiple Choice

Other than forming a larger circle what is the difference between point A, B, and D in this diagram? (Chem3.01 Lv2)

• They are all different letters

• They are at different energy levels

• They make larger circles around the nucleus

• They are all at the same energy level

Multiple Choice

According to the energy shell model, an electron cannot reside at ___ in this figure?

• A

• B

• C

• D

Multiple Choice

Electrons occupy space around the nucleus at ____________. (Chem3.01 Lv1)

• certain energy levels

• a specific points and never move

• at random locations

• anywhere it wants to be

Multiple Choice

Which of the following pictures represents energy shells around an atom (Chem 3.01 Lv 1)

Electron Shells and Subshells

• Each electron shell is at a different energy level.

• Electrons in Electron shell 1, the one closest to the nucleus, have the lowest energy level.

• As you move away from the nucleus the electrons are at a higher energy level (allowing them to be attracted to the nucleus from further away)

Electron Shells and Subshells

• The further you move out the higher the energy level.

• Level 2 has a higher energy level than level 1

• Level 3 has a higher energy level than level 2

• ...and so on up to 4 energy levels

Electron Shells and Subshells

• The first electron shell is small and very close to the nucleus.

• It only has enough room to hold two electrons

Electron Shells and Subshells

• Electron shells past the 1st have more room and can hold more electrons.

• Any electron shell that has more than 2 electrons develop what is called subshells

• This is because the negative charge of each electron repulses (pushes away) other electrons.

Electron Shells and Subshells

• Electrons pushing each other away causes slightly different energy levels between electrons giving us the subshells.

• Each electron shell has a number of subshells equal to its energy level up to electron shell 4.

Electron Shells and Subshells

• These subshells are labeled as follows.

• 1st subshell is labeled s

• 2nd subshell is labeled p

• 3rd subshell is labeled d

• 4th subshell is labeled f

Electron Shells and Subshells

You can see the electron shells (levels) and subshells in the diagram to the right.

Multiple Choice

Looking at the following figure, how many subshells will the outermost shell have? (Chem3.01 Lv2)

• 1

• 2

• 3

• 4

Multiple Choice

How can you determine the number of subshells an energy shell has? (Chem3.01 Lv2)

• An energy shell has a number of subshells equal to its energy shell number. For example, energy shell 1 has 1 subshell.

• You can up the number of electrons and divide by the number of shells.

• You can only determine the number by observing the atom

• An energy shell has an equal number of subshells. All energy levels have 4 subshells.

Multiple Choice

Which statement is true about electrons in different energy shells? (Chem 3.01 Lv3)

• Electrons closest to the nucleus have the lowest energy, while the electrons farthest away from the nucleus have the highest energy.

• Electrons closest to the nucleus have the highest energy, while the electrons farthest away from the nucleus have the lowest energy.

• All electrons in different energy shells have the same amount of energy.

• Electrons only have one energy there so they only exist at one energy shell.

Multiple Choice

Which electron would have the most energy? (Chem3.01 Lv3)

• An electron in energy shell 1

• An electron in energy shell 2

• An electron in energy shell 4

• An electron in energy shell 3

Multiple Choice

How can the energy shells around the nucleus be described?(Chem3.01 Lv2)

• They are all identical to each other just larger orbits

• Each energy shell has electrons at different energy levels

• That the shells get harder as you move away from the nucleus

• Energy shells or levels are a scientific myth

Multiple Choice

How many electrons can the first energy shell hold?

• 1

• 2

• 8

• 0

Subshells and orbitals

• Each subshell can be further divided into a subgroup called orbitals.

• Again this is because of the electron's negative charge pushing away other electrons.

Subshells and orbitals

• Each subshell has a different number of orbitals

• S only has 1

• P has 3

• d has 5

• and f hs 7

• You only need to know how many orbitals in each subshell. But their shapes can be seen to the right.

Subshells and orbitals

• Each orbital represents mathematically the most likely region to find an electron

• We can not know for sure the exact location of an electron.

Subshells and orbitals

• Each orbital can hold 2 electrons

• so the s subshell with only 1 orbital can only hold 2 electrons

• The p subshell with 3 orbitals can hold a total of 6 electrons (2 electrons x 3 orbitals)

• The d subshell with 5 orbitals can hold 10 electrons

• The f subshell with 7 orbitals can hold 14 electrons.

Multiple Choice

Which of the following are correct about orbitals? (Chem3.01 Lv3)

• s type subshells have 1 orbital, p-type has 3 orbitals, d type has 5 orbitals, and f type has 7 orbitals.

• s type subshells have 7 orbitals, p-type has 5 orbitals, d type has 3 orbitals, and f type has 1 orbital.

• s type subshells have 1 orbital, p-type has 7 orbitals, d type has 5 orbitals, and f type has 3 orbitals.

• They all have the same number of orbitals.

Multiple Choice

Which statement is true about electrons in different energy shells? (Chem 3.01 Lv3)

• Electrons closest to the nucleus have the lowest energy, while the electrons farthest away from the nucleus have the highest energy.

• Electrons closest to the nucleus have the highest energy, while the electrons farthest away from the nucleus have the lowest energy.

• All electrons in different energy shells have the same amount of energy.

• Electrons only have one energy there so they only exist at one energy shell.

Multiple Choice

Which electron would have the most energy? (Chem3.01 Lv3)

• An electron in energy shell 1

• An electron in energy shell 2

• An electron in energy shell 4

• An electron in energy shell 3

Multiple Choice

How many electrons can the first energy shell hold?

• 1

• 2

• 8

• 0

Multiple Choice

How many p orbitals are there in a sublevel?

• 2
• 1
• 4
• 3

Multiple Choice

How many d orbitals are there in a given sublevel?

• 1
• 3
• 5
• 7

Multiple Choice

What is the maximum number of electrons that an orbital can have?

• 1 electron
• 2 electrons
• 3 electrons
• 4 electrons

Multiple Choice

Electron Subshell

• a region in an atom where there is a high probability of finding electrons.

• an electron that is found in the outermost shell of an atom and that determines the atom’s chemical properties.

• The energy level at which electrons orbit the nucleus of an atom

• a subdivision of electron shells

Multiple Choice

Electron Shell

• a region in an atom where there is a high probability of finding electrons.

• an electron that is found in the outermost shell of an atom and that determines the atom’s chemical properties.

• The energy level at which electrons orbit the nucleus of an atom

• a subdivision of electron shells

Multiple Choice

Orbital

• a region in an atom where there is a high probability of finding electrons.

• an electron that is found in the outermost shell of an atom and that determines the atom’s chemical properties.

• The energy level at which electrons orbit the nucleus of an atom

• a subdivision of electron shells