Question

determine whether each statement is true or false.
a sodium cation has eight valence electrons.
a chloride anion has seven valence electrons.
both the bohr model and the lewis dot structure represent an ionic bond formed between two nonmetal atoms.
valence electrons are shown in the bohr model of a chloride anion.

Explanation:

• Sodium (Na) has an atomic number of 11. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{1}\). When it forms a cation (\(Na^{+}\)), it loses one electron (the 3s electron). The resulting electron configuration is \(1s^{2}2s^{2}2p^{6}\), which has 8 valence electrons (the electrons in the outermost shell, which is the second shell here with \(n = 2\) and \(2s^{2}2p^{6}\)). So, the statement "A sodium cation has eight valence electrons" is True.
• Chlorine (Cl) has an atomic number of 17. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}\). When it forms an anion (\(Cl^{-}\)), it gains one electron. The electron configuration becomes \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\), which has 8 valence electrons (in the third shell with \(n=3\) and \(3s^{2}3p^{6}\)). So, the statement "A chloride anion has seven valence electrons" is False.
• Ionic bonds are formed between a metal and a non - metal. Non - metal atoms form covalent bonds (sharing of electrons). The Bohr model and Lewis dot structure are not used to represent ionic bonds between two non - metal atoms. So, the statement "Both the Bohr model and the Lewis dot structure represent an ionic bond formed between two nonmetal atoms" is False.
• The Bohr model shows all the electrons in an atom or ion arranged in shells. For a chloride anion (\(Cl^{-}\)), the Bohr model will show the valence electrons (in the outermost shell). So, the statement "Valence electrons are shown in the Bohr model of a chloride anion" is True.

Answer:

1. True
2. False
3. False
4. True