Question

aks 3f metal reactivity
reactivity increases to ____ & ____
the most reactive metal family are the ____. they are metals. of those, the most reactive is __. they are the most reactive because ____
the most unreactive/stable elements are the ____ because ____
aks 3h periodic trends
atomic radius: ______
atoms get smaller as the protons in the nucleus ____ across a row because there is more ____ between the nucleus and the electro
atoms get larger as you go down a row because there are ______ levels added around the nucleus

Explanation:

The problem is about metal reactivity and periodic trends (atomic radius), which falls under Chemistry (a subfield of Natural Science). For metal reactivity: Reactivity increases to the left and down. The most reactive metal family is alkali metals (Group 1), they are metals. Of those, francium is the most reactive (or cesium, but francium is more reactive) because as you go down Group 1, atomic size increases, ionization energy decreases, so it's easier to lose the valence electron. The most unreactive/stable elements are noble gases (Group 18) because they have a full valence shell (8 electrons, except He with 2), so they don't readily gain or lose electrons. For atomic radius: Atomic radius is the distance from the nucleus to the valence electron. Atoms get smaller as protons in the nucleus increase across a row (period) because there is more positive charge (protons) pulling the electrons closer, so the attraction between the nucleus and electrons increases, making the atom smaller. Atoms get larger as you go down a column (group) because there are more electron shells (energy levels) added around the nucleus, increasing the distance from the nucleus to the valence electrons.

Answer:

Metal Reactivity Section:

• Reactivity increases to the left and down (on the periodic table).
• The most reactive metal family are the alkali metals (Group 1). They are metals. Of those, the most reactive is francium (or cesium). It is the most reactive because as you move down Group 1, atomic size increases, ionization energy decreases (easier to lose the single valence electron).
• The most unreactive/stable elements are the noble gases (Group 18) because they have a full valence electron shell (8 electrons, or 2 for helium), so they do not readily gain/lose electrons.

Periodic Trends - Atomic Radius Section:

• Atomic Radius: The distance from the nucleus to the outermost (valence) electron.
• Atoms get smaller as the protons in the nucleus increase across a row (period) because there is more attraction between the nucleus and the electrons (more positive charge pulls electrons closer), reducing the atomic size.
• Atoms get larger as you go down a column (group) because there are more electron shells (energy levels) added around the nucleus.