Multiple Choice
Which of the following is classified as an element?
37
views
2. Atoms & Elements
Periodic Table: Classifications
Struggling with General Chemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Which pair of elements together make up approximately seven percent of the Earth's crust?
A
Silicon and oxygen
B
Calcium and sodium
C
Potassium and magnesium
D
Aluminum and iron
Verified step by step guidance1
Understand that the Earth's crust is primarily composed of a few major elements, with oxygen and silicon being the most abundant, making up a large percentage of the crust.
Recognize that aluminum and iron are also significant components of the Earth's crust but in smaller amounts compared to oxygen and silicon.
Recall or look up the approximate percentage composition of the Earth's crust by weight for aluminum and iron combined, which is around seven percent.
Compare this combined percentage to the other pairs listed (silicon and oxygen, calcium and sodium, potassium and magnesium) to see which pair sums to about seven percent.
Conclude that aluminum and iron together make up approximately seven percent of the Earth's crust, based on their known abundance values.
2:40mWatch next
Master Periodic Table Classifications with a bite sized video explanation from Jules
Start learningRelated Videos
Related Practice
Periodic Table: Classifications practice set
Problem sets built by lead tutorsExpert video explanations