Multiple Choice
How many valence electrons does the element argon (Ar) have?
4
views
10. Periodic Properties of the Elements
Valence Electrons of Elements
Struggling with General Chemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Which of the following best describes the core electrons of a strontium (Sr) atom?
A
The electrons in the 1s, 2s, 2p, 3s, 3p, 4s, 3d, and 4p orbitals
B
The electrons in the 4d and 5p orbitals
C
The electrons in the 5s orbital
D
The electrons in the 1s, 2s, and 2p orbitals only
Verified step by step guidance1
Step 1: Understand the difference between core and valence electrons. Core electrons are those in the inner shells that are not involved in chemical bonding, while valence electrons are in the outermost shell and participate in bonding.
Step 2: Write the electron configuration of strontium (Sr), which has an atomic number of 38. The configuration is: $1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2$.
Step 3: Identify the valence electrons for Sr. Since Sr is in group 2, its valence electrons are the electrons in the outermost shell, which is the 5s orbital ($5s^2$).
Step 4: Determine the core electrons by excluding the valence electrons. Core electrons include all electrons in orbitals below the outermost shell: $1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 3d^{10}, 4s^2, 4p^6$.
Step 5: Conclude that the core electrons of Sr are those in the $1s, 2s, 2p, 3s, 3p, 3d, 4s,$ and $4p$ orbitals, matching the first answer choice.
2:32mWatch next
Master Main Group Elements Valence Electrons with a bite sized video explanation from Jules
Start learningRelated Videos
Related Practice
Valence Electrons of Elements practice set
Problem sets built by lead tutorsExpert video explanations