Question

17 multiple choice 1 point rubidium is an alkali metal. strontium is an alkaline earth metal. what is a fundamental difference strontium forms a cation, and rubidium forms an anion. there is no fundamental difference. rubidium is more reactive than strontium. the ionization of strontium is higher than that of rubidium. 18 multiple choice 1 point an isoelectronic series is... a group of ions with the same number of atoms. a group of ions with the same number of electrons. a group of ions in order by increasing the number of electrons. a group of ions with the same charge.

Explanation:

Question 17

• Analyze Option 1: Alkali metals (Rubidium) and alkaline earth metals (Strontium) are both metals, so they tend to lose electrons and form cations. So this option is wrong.
• Analyze Option 2: Alkali metals and alkaline earth metals have different properties (e.g., reactivity, ionization energy), so there is a fundamental difference. This option is wrong.
• Analyze Option 3: Reactivity of alkali metals is higher than alkaline earth metals in the same period. Rubidium (alkali metal) is more reactive than Strontium (alkaline earth metal). This is correct.
• Analyze Option 4: Ionization energy of alkaline earth metals is higher than alkali metals in the same period (Strontium > Rubidium), so this option is correct. Wait, there are two correct options? Wait, let's re - check.

Wait, Rubidium is in group 1, Strontium in group 2, same period. Alkali metals have lower ionization energy (easier to lose electron) and higher reactivity than alkaline earth metals. So:

• Option 3: Rubidium is more reactive than strontium. Correct.
• Option 4: The ionization of strontium is higher than that of rubidium. Correct. But maybe the question has a typo or I made a mistake. Wait, the original options:

Wait, the options are:

1. Strontium forms a cation, and rubidium forms an anion. (Wrong, both form cations)
2. There is no fundamental difference. (Wrong)
3. Rubidium is more reactive than strontium. (Correct, as group 1 metals are more reactive than group 2 in same period)
4. The ionization of strontium is higher than that of rubidium. (Correct, as group 2 has higher ionization energy than group 1 in same period)

But maybe in the question's context, both 3 and 4 are correct? But maybe the intended answer is considering both, but let's check the standard knowledge.
In the periodic table, for elements in the same period (Rubidium and Strontium are in period 5), alkali metals (group 1) have lower ionization energy and higher reactivity than alkaline earth metals (group 2). So both option 3 and option 4 are correct. But maybe the question has a mistake, or I misread. Wait, the user's question is to answer the multiple - choice. Let's assume that maybe the options are as given, and perhaps the intended answers are C and D (if we use C for option 3 and D for option 4). But maybe in the original question, there is a mistake, but according to standard chemistry:

• Option 3: Rubidium is more reactive than strontium. Correct.
• Option 4: The ionization of strontium is higher than that of rubidium. Correct.

Question 18

• Analyze Option 1: Isoelectronic series is not about the same number of atoms. It's about electrons. So wrong.
• Analyze Option 2: An isoelectronic series is a group of ions (or atoms) with the same number of electrons. This is the correct definition.
• Analyze Option 3: Isoelectronic series have the same number of electrons, not increasing number. So wrong.
• Analyze Option 4: Isoelectronic series can have different charges (e.g., \(O^{2 -}\), \(F^{-}\), \(Ne\), \(Na^{+}\), \(Mg^{2+}\) have different charges but same number of electrons). So wrong.

Answer:

(Question 17)
If we consider the options, and the standard knowledge, the correct options are:
C. Rubidium is more reactive than strontium.
D. The ionization of strontium is higher than that of rubidium.