Barium (Ba) and chlorine (Cl) combine in a 1:2 ratio to form barium chloride (BaClâ‚‚) due to their respective charges when they form ions.
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Ion Formation:
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Barium is an alkaline earth metal located in Group 2 of the periodic table. It has two electrons in its outermost shell (valence shell) and tends to lose these two electrons to attain a stable electronic configuration. When barium loses two electrons, it forms a barium cation with a charge of +2: \( \text{Ba}^{2+} \).
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Chlorine is a halogen located in Group 17 of the periodic table. It has seven electrons in its valence shell and tends to gain one electron to achieve a stable configuration like that of a noble gas. When chlorine gains an electron, it forms a chloride anion with a charge of -1: \( \text{Cl}^- \).
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Combining Ions:
- To form an electrically neutral compound, the total positive charge must balance the total negative charge. Since one barium ion has a charge of +2 and one chloride ion has a charge of -1, it takes two chloride ions to balance the charge of one barium ion. Thus, to balance the +2 charge from one \( \text{Ba}^{2+} \) ion, two \( \text{Cl}^- \) ions (each with a -1 charge) are needed: \[ \text{Ba}^{2+} + 2 \text{Cl}^- \rightarrow \text{BaCl}_2 \]
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Final Ratio:
- Therefore, the resulting empirical formula of barium chloride is \( \text{BaCl}_2 \), which indicates that one barium ion combines with two chloride ions in a 1:2 ratio.
In summary, barium and chlorine combine in a 1:2 ratio to satisfy the charge balance between the +2 charge of barium and the -2 total charge from two chloride ions, leading to the formulation of barium chloride (\( \text{BaCl}_2 \)).