Write the complete electronic configuration (no abbreviations) for barium (Ba): (3 pts) a) How many valence electrons does barium have? (3 pts) b) Which material Is more electronegative: Ba or Cd? (3 pts)
The Correct Answer and Explanation is:
Correct Answers:
Electronic configuration of Barium (Ba):
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s²
a) Valence electrons in Barium:
Barium has 2 valence electrons.
b) More electronegative element between Ba and Cd:
Cadmium (Cd) is more electronegative than Barium (Ba).
Explanation (300 words):
Barium (atomic number 56) is a member of Group 2 in the periodic table, classified as an alkaline earth metal. To determine its full electronic configuration, the electrons must be filled in order of increasing energy levels. Starting from hydrogen’s orbital (1s²), electrons are progressively placed into orbitals following the Aufbau principle. The final orbital occupied by Barium is 6s², after filling all the lower-energy orbitals.
The complete electron configuration for Barium is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s²
The outermost electrons in Barium reside in the 6s orbital. These two electrons are considered its valence electrons. Valence electrons are those found in the outermost energy level of an atom and are crucial in determining how an element reacts chemically.
When comparing electronegativity, which is a measure of how strongly an atom attracts electrons in a chemical bond, Cadmium (Cd) and Barium (Ba) show different tendencies. Cadmium, with an atomic number of 48, is found in Group 12 and Period 5, while Barium lies in Period 6. Barium, being further down the periodic table and possessing more electron shells, has a weaker pull on bonding electrons due to increased shielding and distance from the nucleus.
Cadmium, being smaller in size with fewer energy levels and a higher effective nuclear charge relative to its size, has a slightly stronger tendency to attract electrons in bonds. Therefore, Cadmium is more electronegative than Barium. This trend aligns with the general principle that electronegativity decreases down a group and increases across a period from left to right.
