Chap 8: Model of matter-atoms and molecules(updated)

Question 1

What is an atom?

Answer 1

an atom is the simplest unit of elements

Question 2

What is the charge of a neutron?

Answer 2

No charge

Question 3

What is the charge of a proton?

Answer 3

It is positively charged

Question 4

What is the charge of an electron?

Answer 4

It is negatively charged

Question 5

What is the charge of a nucleus?

Answer 5

Since it is made up of neutrons and protons, it is positively charged.

Question 6

What is the…
- relative charge
- relative mass
- position in an atom
for protons?

Answer 6

• +1
• 1
• within the nucleus

Question 7

What is the…
- relative charge
- relative mass
- position in an atom
for neutrons?

Answer 7

• 0
• 1
• within the nucleus

Question 8

What is the…
- relative charge
- relative mass
- position in an atom
for electrons?

Answer 8

• -1
• 1/1840
• around the nucleus

Question 9

Why is an atom electrically neutral?

Answer 9

Since the number of protons and the number of electrons are equal, the positive and negative charges in an atom is balanced.
( and neutrons do not have any charges, thus they do not contribute to the overall charge of an atom )

Question 10

If there are
- 6 protons
- 6 electrons
how many neutrons are there?

Answer 10

6, 7 , or 8
( may vary )

Question 11

*Why is it possible that same types of atoms have varying masses?

Answer 11

Electrons have mass, but they are much lighter as compared to protons and neutrons, thus the mass of the electrons in an atom are considered negligible and do not add up to the mass of an atom

Question 12

What are molecules?

Answer 12

Molecules are made up of two or more atoms that are chemically combined

Question 13

What are the two types of molecules

Answer 13

molecules of an element and molecules of a compound

Question 14

**What are isotopes?

Answer 14

Isotopes are atoms of the same element that have the same number of protons and electrons, but different numbers of neutrons

Question 15

*How do you define ions?

Answer 15

when the number of protons and electrons are not the same

Question 16

If there are 6 protons and 7 neutrons, how many electrons are there in an atom?

Answer 16

6, this is because the number of electrons are equal to the number of protons.

Question 17

How should a nuclide notation be presented.

Answer 17

The mass number is in the top left position, while the atomic number is on the bottom position.

Question 18

What is the mass number in a nuclide notation?

Answer 18

It is the number of protons and neutrons in an atom.
*no electrons bc electron’s mass is considered negligible despite having mass.

Question 18

what is the atomic number/proton number in a nuclide notation?

Answer 18

It is the number of protons in an atom.

Question 18

How do you find the number of neutrons in a sodium atom?

Answer 18

Mass number - number of protons

Question 19

Write a nuclide notation of a sodium atom with 14 neutrons and 11 protons

Answer 19

Mass number: 25
proton number: 11
Because 25 - 11 = 14

*note that the chemical symbol should be Na since that is the chem. symbol for sodium.
*However if they are asking for the nuclide notation of a potassium, chemical symbol should be K

Question 19

How do you write an electronic configuration of a silicon atom. (14 electrons)

Answer 19

2.8.4
( if dk why look at notes )

Question 19

What are valence electrons?

Answer 19

Valence electrons are electrons in the outer shell of an atom. The chemical properties of an element depend on the number of valence electrons.

Question 20

How many electrons can
1. the first shell
2. the second shell
3. the third and onwards shell
hold?

Answer 20

1. holds up to 2 electrons
2. holds up to 8 electrons
3. usually holds up to 8 electrons (theoretically max is 18 )