Question

1. describe the contents of each cell using the terms (where applicable): atoms, element, molecules, compound; mixture, pure substance; solid, liquid or gas. 15. how is energy involved in chemical and physical changes? 16. define the law of conservation section 3 17. a horizontal row of elements in the periodic table is called a(n) periods 18. the symbol for the element in period 2, group 13, is 19. elements that are good conductors of heat and electricity are metals 20. elements that are poor conductors of heat and electricity are non - metals 21. a vertical column of elements in the periodic table is called a(n) group 22. the ability of a substance to be hammered or rolled into thin sheets is called malleable 23. is an element that is soft and easy to cut cleanly with a knife likely to be a metal or a nonmetal? non - metal 24. the elements in group 18, which are generally unreactive, are called noble gases 25. at room temperature, most metals are solid 26. name three characteristics of most nonmetals. 27. name three characteristics of metals. 28. name three characteristics of most metalloids.

Explanation:

Step1: Analyze particle - arrangement

The particles are closely packed in a regular pattern and there are different types of atoms bonded together, forming molecules. It is a solid (S) and a pure substance (PS). Since there are multiple types of atoms in molecules, it is a compound.
- # Answer: Solid, pure substance, compound, molecules
- **Cell B**:
- # Explanation:
## Step1: Analyze particle - arrangement
The particles are more randomly arranged compared to a solid but still close - together, indicating a liquid (L). There are different types of particles present, so it is a mixture (mix). There are molecules of different substances.
- # Answer: Liquid, mixture, molecules
- **Cell C**:
- # Explanation:
## Step1: Analyze particle - arrangement
The particles are far apart and moving freely, indicating a gas (G). There are different types of particles present, so it is a mixture (mix). There are molecules of different substances.
- # Answer: Gas, mixture, molecules
- **Cell D**:
- # Explanation:
## Step1: Analyze particle - arrangement
The particles are closely packed in a regular pattern and all the particles are of the same type, forming molecules. It is a solid (S) and a pure substance (PS). Since all atoms are of the same element, it is an element.
- # Answer: Solid, pure substance, element, molecules

15.

- # Explanation:
## Step1: Chemical changes
In chemical changes, energy is either absorbed (endothermic) or released (exothermic). Bonds are broken and new bonds are formed. For example, in the combustion of a fuel, chemical energy stored in the fuel is released as heat and light.
## Step2: Physical changes
In physical changes, energy is also involved. For melting (solid - to - liquid), energy is absorbed to break the intermolecular forces holding the solid together. For condensation (gas - to - liquid), energy is released as the gas molecules come closer together and form a liquid.
- # Answer: In chemical changes, energy is involved in bond - breaking and bond - forming, and can be absorbed or released. In physical changes, energy is involved in changing the state of matter by altering intermolecular forces.

16.

- # Explanation:
## Step1: General definition
The Law of Conservation states that in a closed system, matter and energy are neither created nor destroyed. In a chemical reaction, the total mass of the reactants is equal to the total mass of the products (Law of Conservation of Mass). In an isolated system, the total energy remains constant (Law of Conservation of Energy).
- # Answer: In a closed system, matter and energy are neither created nor destroyed. In chemical reactions, the total mass of reactants equals the total mass of products, and in an isolated system, the total energy is constant.

18.

- # Explanation:
## Step1: Locate on periodic table
Period 2, Group 13 corresponds to the element boron.
- # Answer: B

23.

- # Explanation:
## Step1: Recall properties
Metals are generally hard, but some alkali metals like sodium are soft and can be cut with a knife. So, an element that is soft and easy to cut cleanly with a knife is likely a metal.
- # Answer: metal

26.

- # Explanation:
## Step1: Recall non - metal properties
Non - metals are poor conductors of heat and electricity. They are often brittle (not malleable or ductile). Many non - metals are gases at room temperature.
- # Answer: Poor conductors of heat, poor conductors of electricity, often gases at room temperature

27.

- # Explanation:
## Step1: Recall metal properties
Metals are good conductors of heat and electricity. They are malleable (can be hammered into thin sheets) and ductile (can be drawn into wires).
- # Answer: Good conductors of heat, good conductors of electricity, malleable

28.

- # Explanation:
## Step1: Recall metalloid properties
Metalloids have properties intermediate between metals and non - metals. They are semiconductors of electricity. They can have a metallic luster. They are somewhat brittle.
- # Answer: Semiconductors of electricity, metallic luster, somewhat brittle

Answer:

14.

• Cell A:
• # Explanation:

Step1: Analyze particle - arrangement

The particles are closely packed in a regular pattern and there are different types of atoms bonded together, forming molecules. It is a solid (S) and a pure substance (PS). Since there are multiple types of atoms in molecules, it is a compound.

• # Answer: Solid, pure substance, compound, molecules
• Cell B:
• # Explanation:

Step1: Analyze particle - arrangement

The particles are more randomly arranged compared to a solid but still close - together, indicating a liquid (L). There are different types of particles present, so it is a mixture (mix). There are molecules of different substances.

• # Answer: Liquid, mixture, molecules
• Cell C:
• # Explanation:

Step1: Analyze particle - arrangement

The particles are far apart and moving freely, indicating a gas (G). There are different types of particles present, so it is a mixture (mix). There are molecules of different substances.

• # Answer: Gas, mixture, molecules
• Cell D:
• # Explanation:

Step1: Analyze particle - arrangement

The particles are closely packed in a regular pattern and all the particles are of the same type, forming molecules. It is a solid (S) and a pure substance (PS). Since all atoms are of the same element, it is an element.

• # Answer: Solid, pure substance, element, molecules

15.

• # Explanation:

Step1: Chemical changes

In chemical changes, energy is either absorbed (endothermic) or released (exothermic). Bonds are broken and new bonds are formed. For example, in the combustion of a fuel, chemical energy stored in the fuel is released as heat and light.

Step2: Physical changes

In physical changes, energy is also involved. For melting (solid - to - liquid), energy is absorbed to break the intermolecular forces holding the solid together. For condensation (gas - to - liquid), energy is released as the gas molecules come closer together and form a liquid.

• # Answer: In chemical changes, energy is involved in bond - breaking and bond - forming, and can be absorbed or released. In physical changes, energy is involved in changing the state of matter by altering intermolecular forces.

16.

• # Explanation:

Step1: General definition

The Law of Conservation states that in a closed system, matter and energy are neither created nor destroyed. In a chemical reaction, the total mass of the reactants is equal to the total mass of the products (Law of Conservation of Mass). In an isolated system, the total energy remains constant (Law of Conservation of Energy).

• # Answer: In a closed system, matter and energy are neither created nor destroyed. In chemical reactions, the total mass of reactants equals the total mass of products, and in an isolated system, the total energy is constant.

18.

• # Explanation:

Step1: Locate on periodic table

Period 2, Group 13 corresponds to the element boron.

• # Answer: B

23.

• # Explanation:

Step1: Recall properties

Metals are generally hard, but some alkali metals like sodium are soft and can be cut with a knife. So, an element that is soft and easy to cut cleanly with a knife is likely a metal.

• # Answer: metal

26.

• # Explanation:

Step1: Recall non - metal properties

Non - metals are poor conductors of heat and electricity. They are often brittle (not malleable or ductile). Many non - metals are gases at room temperature.

• # Answer: Poor conductors of heat, poor conductors of electricity, often gases at room temperature

27.

• # Explanation:

Step1: Recall metal properties

Metals are good conductors of heat and electricity. They are malleable (can be hammered into thin sheets) and ductile (can be drawn into wires).

• # Answer: Good conductors of heat, good conductors of electricity, malleable

28.

• # Explanation:

Step1: Recall metalloid properties

Metalloids have properties intermediate between metals and non - metals. They are semiconductors of electricity. They can have a metallic luster. They are somewhat brittle.

• # Answer: Semiconductors of electricity, metallic luster, somewhat brittle