(Ch 4.) Atoms & Energy

Question 1

Who is John Dalton?

Answer 1

He is the man who coined the Theory of Atoms. (Describing their properties.)

Question 2

How did J.J Thompson arrive at the Plum-Pudding Model?

Answer 2

He discovered that electrons had (-) charge, but atoms are neutral. He argued that the electrons were held in a sphere of positive charge.
Much like blueberries in a muffin.

Question 3

What are the five aspect of John Dalton’s Atomic Theory?

Answer 3

1. Elements are made out of atoms.
2. All atoms of a given element are identical.
3. Atoms of element A, are different than atoms of element B.
4. Atoms of differing elements can come together to form compounds.
5. Atoms are indivisible, and can’t be created or destroyed by chemical reactions.

Question 4

Who is J.J Thompson?

Answer 4

He is the scientist that discovered that electrons are smaller/negatively charged and established the “Plum Pudding Model.”

Question 5

What is J.J Thompson’s theory of Electrons? (What did he discover?) What was the conclusion to this discovery?

Answer 5

1. Electrons are negatively charged.
2. Electrons are TINY.
3. Electrons are uniformly present in different types of substances.
   Conclusion: The plum pudding model.

Question 6

Who is Ernest Rutherford?

Answer 6

The scientist who proved the PP Model incorrect. He coined a new Atomic Theory.

Question 7

Describe the experiment that proved the Plum-Pudding model incorrect?

Answer 7

Rutherford directed tiny particles (alpha particles) at a thin sheet of gold, though most passed through, some bounced back-meaning they had hit something of substance within the element.

Question 8

What did Rutherford’s Gold Foil experiment prove?

Answer 8

1. The existence of the nucleus of the atom.
2. Most of an atom is actually empty space.
3. The # of (+) and (-) particles in any atom must be equal, as atoms are electrically neutral.

Question 9

What are the charges of the three particles found within an atoms?

Answer 9

Protons (+)
Neutrons (neutral)
Electrons (-)

Question 10

What are the masses in AMU of Protons, Electrons, Neutrons?

Answer 10

P: 1.0073
E: 1.0087
N: .00055

Question 11

What is an Atomic Number? (Z)

Answer 11

The amount of protons in an element.

Question 12

How are the elements generally organized in the periodic table.

Answer 12

Vertically: Similar properties
Horizontally: Atomic mass (least to most-left to right)

Question 13

What is a elements chemical symbol?

Answer 13

(Be) (O), the abbreviation of the element name

Question 14

The elements in the periodic table are generally classified into three groups. What are they? Where are they on the table?

Answer 14

• Metals (left and center)
• Metalloids (a diagonal line between metals and non metals)
• Non-Metals (the right corner)

Question 15

What are three properties of Metals?

Answer 15

1. They are great conductors.
2. They are malleable and ductile (thinned into wires)
3. They tend to LOOSE electrons when they undergo chemical changes.

Question 16

What are three properties of Non-Metals?

Answer 16

1. Some are solid at room temp and some are gases.
2. They are poor conductors.
3. They tend to GAIN electrons when they undergo chemical changes.

Question 17

What are two properties of Metalloids?

Answer 17

1. Their properties are generally an intermediate between metals and non-metals.
2. Great semiconductors. (electricity flows through easily)

Question 18

Explain Group Elements VS. Transition Elements.

Answer 18

Main-group elements are in prime spots in the periodic table that make their properties easier to predict. (That’s it!)

Question 19

What are Alkali Metals? Where are they found on the periodic table?

Answer 19

1. VERY reactive metals.
2. 1A, or the furthest left column
   (ex. Lithium, Sodium)

Question 20

What are Alkaline Earth Metals? Where are they found on the periodic table?

Answer 20

1. Decently reactive metals
2. 2A, the second most left column.
   (ex. Calcium, Magnesium)

Question 21

What are Halogens? Where are they found on the periodic table?

Answer 21

1. VERY reactive nonmetals.
2. 7A, the second to most right column.
   (ex. Iodine, Bromine)

Question 22

What are Noble Gases? Where can they be found on the periodic table?

Answer 22

1. Non-reactive gases.
2. 8A, the right most column.

Question 23

What is an Ion?

Answer 23

A charged particle.

Question 24

What is a Cation?
What is an Anion?

Answer 24

1. A positively charged particle
2. A negatively charged particle

Question 25

What is an Isotope?

Answer 25

An atom with the same number of protons but different number of neutrons. (flavors of ice cream)

Question 26

To the left of the chemical symbol there are two symbols. What do they represent?
(Top Left) (A)
(Bottom Left) (Z)

Answer 26

A= mass number
Z= atomic number

Question 27

How do you find the mass number of an element? (A)

Answer 27

Add the number of protons and neutrons.

Question 28

How do you find the atomic number of an element? (Z)

Answer 28

It’s the number of protons in an element.

Question 29

The atomic mass seen in a periodic table is the _____ of the mass of the isotopes of that element.

Answer 29

Average.

Question 30

How do you find the Atomic Mass?

Answer 30

Multiply the average of an isotope by the mass and find the average of all the isotopes.
(25%, mass 2g) (75%, mass 3g)= Average of 1.375g

Question 31

What is the difference between the Atomic Mass and the Mass Number?

Answer 31

1. Atomic Mass- An average of the isotopes weight.
2. Mass Number- Protons+Neutrons

Question 32

What is the difference between Atomic Mass and the Atomic Number?

Answer 32

1. Atomic Mass- An average of the isotopes weight.
2. Atomic Number- How many protons are in an element.