Which of the following characteristics most directly determines an element's metallic character and its reactivity as a metal?

• A. The tendency to lose electrons and form positive ions
• B. The atomic mass of the element
• C. The number of neutrons in the nucleus
• D. The ability to gain electrons and form negative ions

Answer: (A)

Verified step by step guidance

1. Understand that metallic character refers to how readily an element loses electrons to form positive ions (cations), which is a key property of metals.
2. Recognize that reactivity of metals is largely determined by their tendency to lose electrons during chemical reactions, making them more reactive if they lose electrons easily.
3. Evaluate the options given: atomic mass and number of neutrons do not directly affect electron loss or gain; the ability to gain electrons relates more to nonmetals.
4. Identify that the tendency to lose electrons and form positive ions directly relates to both metallic character and metal reactivity.
5. Conclude that the characteristic most directly determining metallic character and metal reactivity is the element's tendency to lose electrons and form positive ions.