Final answer:
The number of valence electrons in an element is typically determined by its group number in the periodic table. Examples include 7 valence electrons for fluorine, 6 for oxygen, and others, with transition metals having a variable number of valence electrons.
Step-by-step explanation:
Valence Electrons of Elements
To determine the number of valence electrons for an element, we refer to its group in the periodic table. Most groups have a corresponding number of valence electrons, except for transition metals (groups 3-12). For example, elements in Group 1 have 1 valence electron, while Group 17 elements have 7, as they are halogens like fluorine.
Fluorine (F) - Group 17: 7 valence electrons
Oxygen (O) - Group 16: 6 valence electrons
Phosphorus (P) - Group 15: 5 valence electrons
Carbon (C) - Group 14: 4 valence electrons
Calcium (Ca) - Group 2: 2 valence electrons
Hydrogen (H) - Group 1: 1 valence electron
Nitrogen (N) - Group 15: 5 valence electrons
Iron (Fe) - Transition metal: variable valency
Argon (Ar) - Group 18: 8 valence electrons
Potassium (K) - Group 1: 1 valence electron
Sulfur (S) - Group 16: 6 valence electrons
Helium (He) - Group 18: 2 valence electrons
Magnesium (Mg) - Group 2: 2 valence electrons
Sodium (Na) - Group 1: 1 valence electron
Lithium (Li) - Group 1: 1 valence electron
Zinc (Zn) - Transition metal: variable valency
Iodine (I) - Group 17: 7 valence electrons
Barium (Ba) - Group 2: 2 valence electrons
Aluminum (Al) - Group 13: 3 valence electrons
Xenon (Xe) - Group 18: 8 valence electrons
Copper (Cu) - Transition metal: variable valency
Transition metals can have variable valency which means the number of valence electrons they use for bonding can vary.