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Tori - 8th Grade Science > Unit 3 Exam > Flashcards

Unit 3 Exam Flashcards

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1
Q

Which contribution is a modification to Thomson’s plum pudding model?

A

A positively charged nucleus sits at the center of an atom.

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2
Q

An atom with 4 protons, 5 neutrons, and 4 electrons has an atomic mass of

A

9 amu

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3
Q

Which of the following statements does not describe the structure of an atom?

Inside the nucleus of an atom are protons and neutrons.
Protons are positively charged sub-atomic particles.
Electrons are negatively charged sub-atomic particles.
Most of the mass of an atom comes from the electron cloud.

A

Most of the mass of an atom comes from the electron cloud.

FALSE

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4
Q

There are more electrons than protons in a negatively charged atom. T/F?

A

True

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5
Q

A neutral atom of aluminum has 13 protons and how many electrons

A

13

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6
Q 
Which of the following elements has the highest atomic mass?
Helium: 2 protons and 2 neutrons
Nitrogen: 7 protons and 7 neutrons
Oxygen: 8 protons and 8 neutrons
Hydrogen: 1 proton and no neutrons
A

Oxygen: 8 protons and 8 neutrons

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7
Q

Ernest Rutherford

A

Positively charged nucleus

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8
Q

J.J. Thomson

A

Plum pudding model

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9
Q

John Dalton

A

Atoms indivisible

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10
Q

James Chadwick

A

Discovery of neutrons

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11
Q 
Which of the following elements has the largest atomic radius?
Silicon	
Aluminum
Sulfur
Phosphorous
A

Aluminum

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12
Q 
Which of the following elements is the most reactive? 
Beryllium
Calcium
Magnesium
Barium
A

Barium

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13
Q

Neon

A

Nonreactive gas

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14
Q

Boron

A

Has properties of both metals and nonmetals

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15
Q

Barium

A

Great conductor of heat and electricity

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16
Q

Potassium

A

Malleable and highly reactive

17
Q

A neutral atom of beryllium (Be) has an average mass of 9 amu and 4 electrons. How many neutrons does it have?

A

5

18
Q

The element chlorine is represented by the symbol

A

Cl

19
Q

Use your periodic table of elements. Take any element from the first column, except for hydrogen and lithium, and answer the following questions:

What is the element’s name and symbol?
Is it a metal, nonmetal, or metalloid?
Which family does it belong to?
How many protons, neutrons, and electrons does its neutral atom have?

Francium

A
  1. Fr, Francium
  2. Francium is a non-metal
  3. Francium belongs to the alkali metal family.
  4. Francium 87 Protons, 136 Neutrons, 87 Electrons
20
Q

Which item is made from a basic ingredient?

A

Toothpaste

21
Q

Which description is not a property of a base?

Turns litmus paper red
Bitter taste
Caustic
pH higher than 7

A

Turns litmus paper red

22
Q

Ion

A

An atom or molecule that has a positive or negative charge

23
Q

Acid

A

A compound that increases hydrogen ions (H+) when it is dissolved in a solution

24
Q

Alkaline

A

A compound that increases the hydroxide ions (OH−) when it is dissolved in a solution

25
Q

pH

A

A value from 0 to 14 that is used to specify how acidic or basic a compound is when it is dissolved in water

26
Q

Which description is not a property of an acid?

Sour taste
Corrosive
Slimy feel
Dissolves metals

A

Slimy feel

27
Q

Which number represents an acidic pH, 4 or 9

A

4

28
Q

Which description of salt is a physical property?

No combustion
Makes ionic bonds
Product of mixing acids and bases
Solid does not conduct electricity

A

Solid does not conduct electricity

29
Q

Which substances will make a salt when combined?

Vinegar and antacids
Soda and wine
Soap and ammonia
Fertilizer and detergent

A

Vinegar and antacids

30
Q

Which of the following techniques can be used to separate a homogeneous mixture into its component parts?

A

Apply pressure

31
Q

Heterogeneous mixtures can be physically separated into their individual components.
T/F?

A

True

32
Q

Heterogeneous

A

Mixture that has its different components mixed unevenly within the substance

33
Q

Colloid

A

A mixture in which microscopically insoluble particles are suspended throughout another substance

34
Q

Emulsion

A

A mixture in which two or more liquids are mixed that normally are not mixable

35
Q

Homogeneous

A

Mixture that has its different components mixed evenly within the substance

36
Q

What makes a pure substance different from a heterogeneous mixture?

A

The components of a pure substance are single elements or compounds instead of a mixture of compounds.

37
Q

The process of filtration was used to separate a sample into its components. What conclusion about the sample can be formed based on the technique used?

A

It was a heterogeneous mixture.

38
Q

Which substance is a heterogeneous mixture

Cereal
Silver
Nickel
Shampoo

A

Cereal

Tori - 8th Grade Science (9 decks)

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