To determine which two elements have the same number of valence electrons, we need to find out the number of valence electrons for each given element.
1. Barium (Atomic Number 56):
- Barium is in the 6th period.
- The valence electrons of elements in the 6th period are found by subtracting 54 from their atomic number.
- Thus, Barium has [tex]\( 56 - 54 = 2 \)[/tex] valence electrons.
2. Neon (Atomic Number 10):
- Neon is in the 2nd period.
- The valence electrons of elements in the 2nd period are found by subtracting 2 from their atomic number.
- Thus, Neon has [tex]\( 10 - 2 = 8 \)[/tex] valence electrons.
3. Silicon (Atomic Number 14):
- Silicon is in the 3rd period.
- The valence electrons of elements in the 3rd period are found by subtracting 10 from their atomic number.
- Thus, Silicon has [tex]\( 14 - 10 = 4 \)[/tex] valence electrons.
4. Carbon (Atomic Number 6):
- Carbon is in the 2nd period.
- The valence electrons of elements in the 2nd period are found by subtracting 2 from their atomic number.
- Thus, Carbon has [tex]\( 6 - 2 = 4 \)[/tex] valence electrons.
Now, we can compare the number of valence electrons for each element:
- Barium: 2 valence electrons
- Neon: 8 valence electrons
- Silicon: 4 valence electrons
- Carbon: 4 valence electrons
The elements that share the same number of valence electrons are Silicon and Carbon, each with 4 valence electrons.
Hence, the correct elements are Silicon and Carbon.
