Gizmos Student Exploration: Electron Configuration Answer Key Latest 2023/2024 A+ Score (Actual Exam)

Student Exploration: Electron Configuration

Vocabulary: atomic number, atomic radius, Aufbau principle, chemical family, diagonal rule, electron configuration,

Hund’s rule, orbital, Pauli exclusion principle, period, shell, spin, subshell

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

1. Elvis Perkins, a rather shy fellow, is getting on the bus shown at right. Which seat do you

think he will probably sit in? Mark this seat with an “E.”

The one in the top left hand corner

2. Marta Warren gets on the bus after Elvis. She is tired after a long day at work. Where do you

think she will sit? Mark this seat with an “M.”

She would sit in the lower left corner to be by a window

3. In your experience, do strangers getting on a bus like to sit with other people if there is an

empty seat available? no

Gizmo Warm-up

Just like passengers getting on a bus, electrons orbit the nuclei of atoms in particular patterns. You will discover these

patterns (and how electrons sometimes act like passengers boarding a bus) with the Electron Configuration Gizmo™.

To begin, check that Lithium is selected on the PERIODIC TABLE tab.

1. The atomic number is equal to the number of protons in an atom.

How many protons are in a lithium atom? 3

2. A neutral atom has the same number of electrons and protons.

How many electrons are in a neutral lithium atom? 3

3. Select the ELECTRON CONFIGURATION tab. Click twice in the 1s box at upper left and once in the 2s box.

Observe the atom model on the right.

A. What do you see? Two atoms floating in the Bohr model

B. Click Check. Is this electron configuration correct? no

Activity A:

Small atoms

Get the Gizmo ready:

● On the PERIODIC TABLE tab, select H (hydrogen).

● Select the ELECTRON CONFIGURATION tab.

● Click Reset.

Introduction: Electrons are arranged in orbitals, subshells, and shells. These levels of organization are shown by the

boxes of the Gizmo. Each box represents an orbital. The subshells are labeled with letters (s, p, d, and f) and the shells

are labeled with numbers.

Question: How are electrons arranged in elements with atomic numbers 1 through 10?

1. Infer: Based on its atomic number, how many electrons does a hydrogen atom have? 1

2. Arrange: The Aufbau principle states that electrons occupy the lowest-energy orbital. Click once in the 1s box to

add an electron to the only orbital in the ssubshell of the firstshell.

Click Check. What is the electron configuration of hydrogen? 1s1

3. Arrange: Click Next element to select helium. Add another electron to the 1s orbital. The arrows represent the

spin of the electron. What do you notice about the arrows?

the arrows represent the number of electrons surrounding the atom

The Pauli exclusion principle states that electrons sharing an orbital have opposite spins.

4. Check your work: Click Check. What is the electron configuration of helium? 1s2

5. Arrange: Click Next element and create electron configurations for lithium, beryllium, and boron. Click Check

to check your work, and then list each configuration below:

Lithium:1s2 2s1 Beryllium:1s1 2s2 Boron:1s1 2s2 2p1

6. Arrange: Click Next element to select carbon. Add a second electron to the first 2p orbital.

Click Check. What feedback is given? electrons aren’t properly arranged

7. Rearrange: Hund’s rule states that electrons will occupy an empty orbital when it is available in that subshell.

Rearrange the electrons within the 2p subshell and click Check.

Is the configuration correct now? yes 1s

Show the correct configuration in the boxes at right: 2s 2p

8. Compare: How are the electrons in the 2p subshell similar to passengers getting on a bus?

9. Practice: In the spaces below, write electron configurations for the next four elements: nitrogen, oxygen, fluorine,

and neon. When you are finished, use the Gizmo to check your work. Correct any improper configurations.

Nitrogen configuration: 1s2 2p2 2p3

Oxygen configuration: 1s2 2s2 2p4

Fluorine configuration: 1s2 2s2 2p5

Neon configuration: 1s2 2s2 2p6

10. Apply: Atoms are most stable when their outermost shell is full. If their outermost shell is not full, atoms tend to

gain, lose, or share electrons until the shell fills up. While doing this, atoms react and form chemical bonds with

other atoms. Based on this, what can you infer about the reactivity of helium and neon? they’re very stable

elements

11. Think and discuss: Select the PERIODIC TABLE tab, and look at the second row, or period, of the table. How

doesthisrow reflect the subshells of the second shell?

It tells you which row the element is in which shows you how many atoms are in the outer shell

Activity B:

Atomic radii

Get the Gizmo ready:

● On the PERIODIC TABLE tab, select Na (sodium).

● Select the ELECTRON CONFIGURATION tab.

Question: How do the radii of atoms change across a period of the periodic table

1. Predict: Positively charged protons in the nucleus of an atom are attracted to negatively charged electrons.

How do you think the atomic radii will change as electrons are added to a shell?

I think that electrons are added to the inner most shell first and work their way out_

2. Arrange: Create a proper electron configuration for sodium. After clicking Check, note the Electron configuration

and the Atomic radius now listed at right.

Sodium electron configuration: 1s2

2s2

2p6

3s1 Atomic radius: 190 picometers

3. Compare: Click Next element, and then add an electron to the magnesium atom. Click check, and record the

electron configuration and atomic radius below.

Magnesium electron configuration: 1s2

2s2

2p6

3s2 Atomic radius: 145 picometers_

4. Gather data: Create electron configurations for the next six elements. Record the electron configuration and

atomic radius of each. (Note: The symbol for picometer is pm.)

Element Number of Electron Atomic radius

electrons configuration (pm)

Aluminum 13 1s2

2s2

2p6

3s2

3p 118

Silicon 14 1s2

2s2

2p6

3s2

3p2

111

Phosphorus 15 1s2

2s2

2p6

3s2

3p3 98

Sulfur 16 1s2

2s2

2p6

3s2

3p4

88

Chlorine 17 1s2

2s2

2p6

3s2

3p5

78

Argon 18 1s2

2s2

2p6

3s2

3p6

71

5. Analyze: How does the atomic radius change across a period of the periodic table?

The further down you go, the more the atomic radius goes down

6. Interpret: Select the ATOMIC RADIUS tab. What do you notice? The scatter plot dots go down in a linear

fashion

7. Predict: On the ATOMIC RADIUS tab click Clear. Select the PERIODIC TABLE tab. Elements in the same

column of the periodic table are called chemical families, or groups.

How do you think the size of atoms will change from top to bottom within a chemical family?

I’m assuming that the bigger the atoms, the atomic radius goes down

8. Test: Hydrogen, lithium, and sodium are all in the same chemical family. Use the Gizmo to find the atomic radius

of each, and list them below.

Hydrogen radius: 53 Lithium radius:167 Sodium radius: 190

9. Analyze: How does the atomic radius change as you go from the top to the bottom of a chemical family? the

10. Challenge: Think about the factors that control atomic radius and the patterns you’ve seen.

A. Why does the atomic radius decrease as electrons are added to a shell because the protons are

increasing

B. Why does the atomic radius increase as you go from the top to the bottom of a chemical family

one proton has a greater effect than one electron

11. Think and discuss: Compare the electron configurations of hydrogen, lithium, and sodium. Why do you think

these elements are grouped in the same family?

Because their PM goes down (almost) in a linear fashion. Therefore, they would be in that order due to

the decreasing PM

Activity C:

The diagonal rule

Get the Gizmo ready:

● On the PERIODIC TABLE tab, select Ar (argon).

● Select the ELECTRON CONFIGURATION tab.

● Turn on Show number of electrons.

Introduction: Beyond argon, it is a bit tricky to determine which subshell gets filled next. There are several rules that

scientists use to determine the electron configurations of larger atoms.

Question: How are the electron configurations of elements beyond argon determine

1. Arrange: Create the correct electron configuration for argon. Then, click Next element to get to potassium (K).

Click once in the first 3d orbital, and then click Check.

What feedback is given? _correct electron configuration

2. Rearrange: As it happens, the 4s subshell is a lower-energy subshell than 3d, so it is filled first. Remove the electron

from the 3d orbital and place it in the 4s orbital. Click Check. (Note: For simplicity, all but the outer shell

electrons will disappear on the Bohr Model.)

Is this configuration correct?yes What is the configuration? 1s2 2s2 2p6 3s2 3p6 4s1

Arrange: Click Next element and add an electron for calcium. Click Check.