2.1 - The Nature Of Matter Flashcards Preview

Biology - Chapter 2 Chemisty Of Life > 2.1 - The Nature Of Matter > Flashcards

Flashcards in 2.1 - The Nature Of Matter Deck (36):
1

What is an atom?

The smallest unit of matter that cannot be broken down by chemical means.

2

What are the 3 subatomic particles of an atom?

Protons, Neutrons, Electrons

3

The charge of a proton?

Positive

4

What is the charge of a neutron?

No charge (neutral)

5

What is the charge of an electron?

Negative
Are found in the space around the nucleus(electron cloud) in constant motion

6

What is the nucleus? What is it made of?

The center of the atom made of protons and neutrons

7

What 2 subatomic particles are attracted to each other? Why?

Protons and electrons
They are oppositely charged

8

Compare the numbers of elections and protons

They are typically the same causing the atom to have no charge.

9

What is an element?

Substance made of only one kind of atom (pure substance)

10

What is an atomic number?

Number of protons in the nucleus of an atom

11

How many elements are there?

118 distinct atoms: 90 natural, 28 created in laboratory

12

What is the atomic symbol of an element?

1, 2, 3 letter symbol used to represent elements

13

What is an isotope?

Atoms of an element that contain different numbers of neutrons

14

What is the mass number?

Number of protons plus the number of neutrons
Used to identify isotopes

15

What does radioactive isotopes mean?

The nuclei are unstable and break down at a constant rate over time

16

What is a chemical bond?

Force that joins atoms

17

True or false: because they have the same number of electrons, all isotopes of an element have the same chemical properties.

True

18

Give examples of ways radioactive isotopes are used in scientific and practical uses

To determine the ages of rocks and fossils. Radiation from certain isotopes can be used to detect and treat cancer. Also to kill bacteria that cause food to spoil. Can be used as labels or tracers to follow the movement of substances within organisms

19

What is a compound?

Substance made of the joined atoms of two or more elements.

20

How is a compound represented?

By a chemical formula that identifies the elements in the compound and their proportion

21

True or false; the physical and chemical properties of a compound are usually very different from those of the elements from which it is formed

True

22

What are the main types of chemical bonds?

Ionic bonds and covalent bonds

23

What are the electrons that are available to form bonds called?

Valance electrons

24

What is an ionic bond?

Is formed when one or more electrons are transferred from one atom to another

25

What is an ion?

The positively and negatively charged atoms

26

What is the proportion of the following compounds? NaCl, H2O, CO2

1 to 1, 2 to 1, 1 to 2

27

What is covalent bond?

Two or more atoms that share electrons

28

What is the difference between a single and double covalent bond?

A single covalent shares two electrons but a double bond shares four electrons

29

What is a molecule?

A group of atoms held together by covalent bond; they are the smallest unit of most compounds

30

Which level of electron has the least amount of energy?

Inner level - energy increases as you move to outer layers

31

How many electrons are in rows 1,2 and 3?

Row 1 - 2, row 2 - 8, row 3 -8

32

True or false: an atom becomes stable when the outer electron level is empty

False

33

What happens when the outer level of an atom is not full?

It will transfer or share electrons so it can become full

34

What is a cation?

Lost electron (+)

35

What is an anion?

Gained electron (-)

36

Van der Waals forces are what?

Slight attraction between oppositely charged regions of nearby molecules