Question

valence electrons, pages 194-195

1. what are valence electrons?

1. the valence electrons largely determine the _______________ of an

element and are usually the only electrons used in _________________.
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1. is the following sentence true or false? the group number of a representative

element in the periodic table is related to the number of valence electrons it has.

1. what is an electron dot structure?

1. draw the electron dot structure for each of the following atoms.

Explanation:

1. Valence electrons are the electrons in the outermost energy level (valence shell) of an atom. These electrons are involved in chemical bonding.
2. Valence electrons largely determine the chemical properties of an element because they are involved in interactions with other atoms. They are usually the only electrons used in chemical bonding (like ionic or covalent bonding) as they are the outermost and most easily accessible for interaction.
3. For representative elements (groups 1, 2, 13 - 18), the group number (for main - group elements) is related to the number of valence electrons. For example, group 1 elements have 1 valence electron, group 2 has 2, group 13 has 3, and so on (up to group 18 with 8, except He with 2). So the statement is true.
4. An electron dot structure (also called Lewis dot structure) is a diagram that shows the valence electrons of an atom as dots around the symbol of the element. The symbol represents the nucleus and the inner - shell electrons, and the dots represent the valence electrons.
5. (Since no specific atoms are given, a general method: For an atom, write its chemical symbol. Then, determine the number of valence electrons. Place one dot at a time on the four sides (top, right, bottom, left) of the symbol, with a maximum of 2 dots per side, until all valence electrons are represented. For example, for Na (sodium, group 1, 1 valence electron), the Lewis dot structure is Na·; for O (oxygen, group 16, 6 valence electrons), it is \(\cdot\ddot{O}\cdot\) (with two dots on the top, two on the right, one on the bottom, and one on the left, or any arrangement as long as there are 6 dots total around O).)

Answer:

1. Valence electrons are the electrons in the outermost energy level of an atom.
2. Chemical properties; chemical bonding
3. True
4. An electron dot structure is a diagram showing an atom's valence electrons as dots around its chemical symbol.
5. (Depends on the specific atoms. For example, if the atom is H: \(\cdot\)H; if the atom is C: \(\cdot\dot{C}\cdot\) (with one dot on top, one on right, one on bottom, one on left))