Open Question
Why don't you find "hunks" of alkali metals lying around in nature?
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2. Atoms & Elements
Periodic Table: Elemental Forms
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Which of the following molecular models represents an element?
A
NH3
B
O2
C
H2O
D
CO2
Verified step by step guidance1
Understand that an element is a pure substance consisting of only one type of atom, while a compound consists of two or more different atoms chemically bonded together.
Examine each molecular formula to identify the types of atoms present:
NH3 contains nitrogen (N) and hydrogen (H) atoms, so it is a compound.
O2 contains only oxygen (O) atoms, so it is a molecule made of a single element.
H2O contains hydrogen (H) and oxygen (O) atoms, so it is a compound.
CO2 contains carbon (C) and oxygen (O) atoms, so it is a compound.
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