Question

model 1 — atoms, particles, and molecules
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elements are defined as pure substances made from only one type of atom. compounds are defined as pure substances made from two or more types of atoms.

1. identify which drawings from question 10 are elements and which are compounds. list the codes for the drawings in the appropriate places below.

elements compounds

1. how are the codes (chemical formulas) for elements different from those for compounds?
2. use what you have just learned about chemical formulas to identify each of the following as an element, a compound or a mixture.

a. br₂ b. nahco₃ c. c₆h₁₂o₆ & h₂o
d. cu & zn e. co₂ f. al

Explanation:

Step1: Recall element and compound definitions

Elements have one - type of atom, compounds have two or more types of atoms.

Step2: Analyze drawings for question 11

Look at each drawing and count atom types.

Step3: Analyze chemical formulas for question 13

• For \(Br_2\), it has one type of atom (bromine), so it's an element.
• For \(NaHCO_3\), it has multiple types of atoms (sodium, hydrogen, carbon, oxygen), so it's a compound.
• For \(C_6H_{12}O_6\&H_2O\), it's a mixture of glucose and water.
• For \(Cu\&Zn\), it's a mixture of copper and zinc.
• For \(CO_2\), it has two types of atoms (carbon and oxygen), so it's a compound.
• For \(Al\), it has one - type of atom (aluminum), so it's an element.

Answer:

11.
Elements: Drawings with only one - type of atom (list the codes of such drawings).
Compounds: Drawings with two or more types of atoms (list the codes of such drawings).

1. Element formulas have one - type of atom symbol, compound formulas have two or more different atom symbols.

13.
a. Element
b. Compound
c. Mixture
d. Mixture
e. Compound
f. Element