Grade 7 Science - Elements and Compounds Vocabulary

Vocabulary flashcards covering core definitions, rules, formulas, and element symbols from Grade 7 Science - Elements and Compounds.

What term refers to anything that has mass and occupies space?

Matter

What is a pure substance made up of only one kind of atom that cannot be chemically broken down into simpler substances?

Element

What is the smallest unit of an element that retains its chemical properties and takes part in a chemical reaction?

Atom

What is a pure substance formed when two or more different elements chemically combine in a fixed ratio?

Compound

What is formed when two or more substances are physically combined and can vary in composition?

Mixture

What are the rules regarding capitalization when writing chemical symbols?

1. The first letter is always capitalized.
2. If a second letter is present, it must be lowercase.

Chemical symbol for Iron

$$Fe$$

Chemical symbol for Copper

$$Cu$$

Chemical symbol for Gold

$$Au$$

Chemical symbol for Silver

$$Ag$$

Chemical symbol for Calcium

$$Ca$$

Chemical formula for Sodium Chloride (common salt)

$$NaCl$$

What is the atomic ratio and composition of one molecule of water ($H_2O$)?

$2$ hydrogen atoms and $1$ oxygen atom

What is the atomic ratio and composition of one molecule of carbon dioxide ($CO_2$)?

$1$ carbon atom and $2$ oxygen atoms

What is the atomic ratio and composition of one molecule of ammonia ($NH_3$)?

$1$ nitrogen atom and $3$ hydrogen atoms

Quiz Question: Is a substance with physical combination and variable composition a compound or a mixture?

A mixture

Quiz Question: What type of methods (physical or chemical) are required to break down a compound into its constituent elements?

Chemical methods