2 is ok.
Think about 3. Does Mg have more reactivity than Na. Does Ca have more reactivity than K?
Think about 1. Except for a few hitches, doesn't atomic mass increase?
Select all that apply.
1 atomic mass increases
2 atomic radius increases
3 reactivity increases
4 valence electrons decrease
2 and 3?
Think about 3. Does Mg have more reactivity than Na. Does Ca have more reactivity than K?
Think about 1. Except for a few hitches, doesn't atomic mass increase?
1. Atomic mass: The atomic mass generally increases when moving left to right across periods as the number of protons and neutrons in the nucleus increases.
2. Atomic radius: The atomic radius generally decreases when moving left to right across periods. This is because, as you move across a period, the number of protons in the nucleus increases, leading to a stronger electromagnetic pull on the electrons, causing them to be pulled closer to the nucleus.
3. Reactivity: Reactivity can vary across periods and depends on various factors, such as the number of valence electrons and the electronegativity of the element. It is not a consistent trend, so it cannot be accurately described as always increasing or decreasing.
4. Valence electrons: Valence electrons generally increase when moving left to right across periods. This is because, as you move across a period, the number of electrons increases, and the outermost electron shell becomes closer to being filled with electrons.
Based on the explanations above, the correct answers are:
- Atomic radius increases (incorrect)
- Reactivity increases (incorrect)
- Valence electrons decrease (incorrect)
None of the answer choices accurately describe the trend when moving left to right across periods.