Question

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. arrange: the aufbau principle states that electrons occupy the lowest - energy orbital. when energy is selected, the orbitals are arranged from lowest - energy at the bottom to highest - energy at the top. 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?

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?

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?
2. arrange: click next element and create electron configurations for lithium, beryllium, boron. click check to check your work, and then list each configuration below:

lithium: ____________ beryllium: __________ boron: ____________

1. arrange: click next element to select carbon. add a second electron to the first

click check. what feedback is given? ______________

1. rearrange: hund’s rule states that electrons will occupy an empty orbital available in that subshell. rearrange the electrons within the 2p subshell.

is the configuration correct now? ______________
show the correct configuration in the boxes at right: 2s 1s

Explanation:

Step1: Determine hydrogen's electron configuration

Hydrogen has 1 electron. According to the Aufbau principle, it goes in the 1s orbital. So the electron - configuration is 1s¹.

Step2: Analyze helium's electrons

Helium has 2 electrons. Both go in the 1s orbital with opposite spins (Pauli exclusion principle). So the electron - configuration is 1s².

Step3: Find lithium's electron configuration

Lithium has 3 electrons. The first 2 fill the 1s orbital and the 3rd goes in the 2s orbital. So the electron - configuration is 1s²2s¹.

Step4: Determine beryllium's electron configuration

Beryllium has 4 electrons. 2 in 1s and 2 in 2s. So the electron - configuration is 1s²2s².

Step5: Find boron's electron configuration

Boron has 5 electrons. 2 in 1s, 2 in 2s, and 1 in 2p. So the electron - configuration is 1s²2s²2p¹.

Answer:

1. 1s¹
2. The two electrons in the 1s orbital have opposite spins.
3. 1s²
4. Lithium: 1s²2s¹; Beryllium: 1s²2s²; Boron: 1s²2s²2p¹
5. (No specific feedback content provided in the question to answer this part precisely. But generally, it may indicate incorrect electron - filling if not following rules.)
6. (No specific initial and final configurations shown to determine if it's correct or not precisely. But the correct 2p configuration for carbon according to Hund's rule has 2 unpaired electrons in separate 2p orbitals, i.e., 1s²2s²2p² with electrons in different 2p orbitals and same - spin.)