# Gizmos Electron Configuration Answers Key

Posted on

For anyone who is looking for the answer key of the Gizmo Electron Configuration, you come to the right page. On this page, you will be able to find the answer key of the Gizmo Electron Configuration. Check out the answer key plus the questions below:

Prior Knowledge Questions

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.”

Answers will vary. [The expected answer is for “E” to be placed on the empty seat, as shown at right.]

1. 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.”

Answers will vary. [The expected answer is for “M” to be placed on the seat closest to the door, as shown at right.]

1. In your experience, do strangers getting on a bus like to sit with other people if there is an empty seat available?

Gizmo Warm-up

1. The atomic number is equal to the number of protons in an atom. How many protons are in a lithium atom? Three protons
2. A neutral atom has the same number of electrons and protons. How many electrons are in a neutral lithium atom? Three electrons
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 electrons are orbiting close to the nucleus, and one electron is orbiting farther out.
B. B. Click Check. Is this electron configuration correct? Yes

Activity A: Small atoms

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? One
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 s subshell of the first shell.

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

1. 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?

One arrow points up, and the other arrow points down.

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

1. Check your work: Click Check. What is the electron configuration of helium? 1s2
2. 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: 1s22s2                   Beryllium: 1s22s2                                        Boron: 1s22s22p1

1. Arrange: Click Next element to select carbon. Add a second electron to the first 2p orbital. Click Check. What feedback is given? Electrons not properly arranged in energy levels.
2. 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

Show the correct configuration in the boxes at right:

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

Sample answer: Like passengers getting on a bus avoiding seats with one occupant,               electrons will avoid orbitals that already have one electron.

1. 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: 1s22s22p3

Oxygen configuration: 1s22s22p4

Fluorine configuration: 1s22s22p5

Neon configuration: 1s22s22p6

1. 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?

Helium and neon have full outer shells, so they won’t react to form chemical bonds.

1. Think and discuss: Select the PERIODIC TABLE tab, and look at the second row, or period, of the table. How does this row reflect the subshells of the second shell?

Sample answer: The second row contains two elements on the left, lithium and beryllium, that represent filling of the 2s subshell. There are six elements on the right (boron through neon) that represent filling of the 2p subshell.

Activity B

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?

Predictions will vary.

1. 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: 1s22s22p63s1

1. 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: 1s12s12p63s1                      Atomic radius: 145 picometers

1. 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.)

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

The atomic radius decreases across a period of the periodic table. [Students may also note that the differences are greatest between the first three elements in the period.]

1. Interpret: Select the ATOMIC RADIUS tab. What do you notice?

Each period starts with a large atom, and then the atoms get smaller across the period.

1. 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?

Predictions will vary.

1. 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.

1. Analyze: How does the atomic radius change as you go from the top to the bottom of a chemical family? The atomic radius increases from top to bottom.
2. 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?

Electrons are attracted to protons. As more electrons (and protons) are added to the atom, the force of attraction between the nucleus and electrons increases. This pulls the electrons closer to the nucleus.

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

As you move down a chemical family, each element has one more shell than the element above. The additional shells result in larger atoms.

1. Think and discuss: Compare the electron configurations of hydrogen, lithium, and sodium. Why do you think these elements are grouped in the same family?

All of these elements have one electron in the outermost s subshell. This similarity in electron configuration will give the three elements similar chemical properties.

Activity C: The diagonal rule

Question: How are the electron configurations of elements beyond argon determined?

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? Electrons not placed in the correct energy levels.

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? 1s22s22p63s23p64s1

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

What is the electron configuration for calcium? 1s22s22p63s23p64s2

4. Arrange: Click Next element and add an electron for scandium. Try different orbitals untilyou find the right one.

What is the electron configuration for scandium? 1s22s22p63s23p63d14s2

5. Observe: Scandium is the first element to contain electrons in the d subshell. How many orbitals does the d subshell have, and how many electrons can fit in the d subshell?

The d subshell has five orbitals and can fit 10 electrons.

6. Infer: Select the PERIODIC TABLE tab. The middle section of the table is a chemical family called the transition metals. Why do you think this section is ten columns wide?

This part of the periodic table represents the filling of the d subshells.

7. Make a rule: The diagonal rule explains which subshell will be filled next. To follow the diagonal rule, move down along an arrow until you reach the end of the arrow. Then move to the start of the next arrow to the right.

A. Which subshell is filled after 4p?5s

B. Which subshell is filled after 6s?4f

C. Which subshell is filled after 5d?6p

8. Practice: Determine the electron configurations of the following elements. Use the Gizmo to check your work. (Note: In some cases, the diagonal rule doesn’t work perfectly. If you submit a theoretically correct configuration, the Gizmo will give you the actual configuration.)

9. Infer: Select the PERIODIC TABLE tab. Earlier you saw that the transition metals represent the filling of the d subshells. Now locate the purple lanthanides and actinides on the bottom rows of the periodic table.

A. How many elements are in the in the lanthanides series?14 elements
B. Which subshell is represented by the lanthanides family?4f
C. Which subshell is represented by the actinides family?5f
D. In general, how is the shape of the periodic table related to electron configurations?