Question

If not as an element, atoms show up as:

A) Molecules and compounds.
B) Protons and neutrons.
C) Electrons and ions.
D) Isotopes and elements.
2. One of the most important compounds is water:

A) H2O
B) CO2
C) NaCl
D) O2
3. It is a major part of the:

A) Earth's atmosphere (as nitrogen).
B) Human body (as oxygen).
C) Earth's crust (as silicon).
D) Plant cells (as carbon).
4. Most of the:

A) Earth's surface is water (as ice).
B) Human body is water (as plasma).
C) Earth's core is water (as steam).
D) Universe is water (as vapor).
5. It is required for chemical:

A) Respiration and photosynthesis.
B) Rusting and corrosion.
C) Decomposition and fermentation.
D) Combustion and precipitation.

Answer 1

Atoms are present in non-elemental forms in biological processes, chemical reactions like decomposition, and phenomena like combustion and precipitation, where they combine, separate, or reorganize to form new substances.

Step-by-step explanation:

Atoms are the building blocks of matter and are present in various forms aside from existing as isolated elements. In the human body, atoms like oxygen are critical for biological functions. Atoms also play a significant role in processes such as decomposition and fermentation where they are rearranged to form new molecules. Another example involves combustion, where atoms combine with oxygen to produce energy and new chemical substances, and precipitation, which is part of the chemical reactions in the water cycle that lead to the formation of precipitation.

These scenarios highlight some of the chemical changes and reactions, such as decomposition reactions, where a single compound breaks down into two or more substances which can be elements, compounds, or mixtures of both. Similarly, in real-world chemistry applications, the decomposition of water through electrolysis results in the production of hydrogen and oxygen gases. A binary compound like mercury (II) oxide undergoes decomposition when heated, producing mercury and oxygen as separate elements.