Final answer:
In the list provided, Hydrogen, H₂, and Sodium, Na, are elements because they consist of only one type of atom. The other substances are chemical compounds. The correct options are A) Hydrogen, H₂ and C) Sodium, Na
Step-by-step explanation:
The student is asking which of the provided substances are elements. An element is a pure chemical substance consisting of one type of atom. Let's assess the options given:
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- Hydrogen, H₂
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- Copper (II) hydroxide, Cu(OH)₂
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- Sodium, Na
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- Zinc hydroxide, Zn(OH)₂
Out of these, Hydrogen, H₂, and Sodium, Na, are elements because they consist of a single type of atom. Hydrogen is made up of hydrogen atoms, while sodium is made up of sodium atoms. Copper (II) hydroxide, Cu(OH)₂, and Zinc hydroxide, Zn(OH)₂, are not elements; they are compounds because they are composed of more than one kind of atom chemically bonded together.