Question

1. which one of the following groups of elements is listed in increasing order based on the percent by mass in earth’s crust? a) magnesium, iron, aluminum c) aluminum, silicon, magnesium b) aluminum, iron, calcium d) magnesium, silicon, calcium 3) which model best represents the volume of each gas in the troposphere?

Explanation:

To solve this, we recall the approximate percent by mass of elements in Earth’s crust:

• Silicon (Si): ~27.7%
• Aluminum (Al): ~8.1%
• Iron (Fe): ~5.0%
• Calcium (Ca): ~3.6%
• Magnesium (Mg): ~2.1%

Analyzing each option:

• Option A: Magnesium (2.1%) → Iron (5.0%) → Aluminum (8.1%). This is increasing, but let’s check others.
• Option B: Aluminum (8.1%) → Iron (5.0%) → Calcium (3.6%). This is decreasing, so invalid.
• Option C: Aluminum (8.1%) → Silicon (27.7%) → Magnesium (2.1%). Silicon (27.7%) > Magnesium (2.1%), so this is decreasing at the end, invalid.
• Option D: Magnesium (2.1%) → Silicon (27.7%) → Calcium (3.6%). Silicon (27.7%) > Calcium (3.6%), so this is decreasing at the end, invalid.

Only Option A has elements in strictly increasing order of percent by mass in Earth’s crust.

Answer:

A) magnesium, iron, aluminum