Chapter 2:Atoms,Molecules,and Ions

Question 0

JJ Thomson

Answer 0

Discoverer of electrons
Plum pudding model
Positive throughout with negative charges spread about

Question 1

Dalton’s atomic theory (4 postulates)

Answer 1

1. each element is composed of extremely small particles called atoms INDIVISIBLE
2. all atoms of a given element are identical, but the atoms of one element are different from the atoms of all the other elements.
3. atoms of one element cannot be changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions.
4. compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms.

Question 2

Electron(mass,charge,location)

Answer 2

9.10938x10^-28 g
Or
5.486x10^-4
Negative 1
Electron cloud
#e = #p
Occupies most of volume of atom

Question 3

Ernest Rutherford

Answer 3

Postulated nuclear model of the atom where most of the mass and all the positive charge was inside a small dense region called the nucleus. Discovered protons
Gold foil and alpha particle experiment

Question 4

James Chadwick

Answer 4

Discoverer of neutrons

Question 5

Proton(mass,charge,location)

Answer 5

1.0073 amu(1amu=1.66054 x10^-24g)
Positive 1
Nucleus
Atoms must have neutral charge so the protons equal the electrons

Question 6

Neutron(mass,weight,location)

Answer 6

1.0087 amu
Neutral
Nucleus

Question 7

Chemistry the study of blank

Answer 7

Matter

Physical changes and chemical and energy changes of.

Question 8

What is matter?

Composed of?

Answer 8

Anything that has mass and occupies space

All matter is composed of elements from periodic table

Question 9

What is an element?

Answer 9

Most basic form of matter that exists under ordinary circumstances.
Cannot be broken down into simpler substances.

Question 10

Element example types(3)

Answer 10

Noble gases,metals, nonmetals

Question 11

Free elements in nature.

Answer 11

Not combined with any other element.

Question 12

Element names.

Answer 12

Usually designated by discoverer, Greek, Latin, Arabic, German origins. After people or places, some name origins uncertain.

Question 13

Element symbols

Answer 13

Most elements have 1-2 letter abbreviations as a symbol

Some more obvious from others some based on previous names.

Question 14

Dalton’s atomic theory 1803(PowerPoint)

Answer 14

(Atoms are most basic matter)

1. atoms are indivisible
2. atoms of the same element have the same properties
3. atoms of different elements have different chemical and physical properties
4. atoms combined in whole number ratios can describe compounds.

Question 15

Size of typical atom

Answer 15

1x10^-8 cm

Question 16

Nuclear model

Answer 16

Theorized by Rutherford

Nucleus compose of protons and neutrons surrounded by electron cloud

Question 17

Atomic number?

Number of what? Which number on periodic table?

Answer 17

Number of protons in an atom

Lower number on periodic table.

Question 18

Mass number? Sum of?

Answer 18

Sum of protons and neutrons, higher number on periodic table/symbol.

Question 19

Isotopes

Answer 19

Most elements occur as mixture of isotopes

Specific isotope is written using isotopic notation

Question 20

Isotopic mass and atomic mass

Answer 20

Mass of an isotope compared to a standard of 12C which has 12 amu( atomic mass unit)
Amu defined as 1/12th the mass of Carbon-12
The atomic mass listed in the periodic table is the weighted average of the atomic masses of all isotopes present in nature.

Question 21

Compound

Answer 21

A unique form of matter of 2 or more elements chemically combined.

Question 22

Molecules

Answer 22

Atoms can join together by a covalent bond, resulting in a molecule.

Question 23

Molecular compounds- molecules of atoms of two different elements

Answer 23

Molecules of atoms of two different elements

Question 24

Covalent bonds

Answer 24

The force holding the atoms together in a molecular compound

Question 25

Chemical formula

Answer 25

Atomic symbols combined

Question 26

Structural formula

Answer 26

Representation of elements and bonds

Question 27

Structural formulas

Answer 27

Show order AND arrangement of specific atoms.

Question 28

Molecular compound(type of bond)

Answer 28

Molecules are held by covalent forces.

Question 29

Ionic compounds(type of bond?)

Answer 29

Held together by electrostatic forces

Question 30

What are ions?

Answer 30

Charged ions or molecules.

Question 31

Can molecular compounds exist as “discrete molecules”?

Answer 31

Yes

Question 32

Positively charged ion?

Answer 32

Cation

Question 33

Negatively charged ion?

Answer 33

Anion.

Question 34

Characteristics of ionic compounds.

Answer 34

Don’t form discrete molecules
Held by ionic bonds
Generally hard and rigid
High melting points

Question 35

Overall charge on any compound

Answer 35

Zero

Question 36

Ions have a characteristic charge.

+1s?

Answer 36

H,Li,Na,K

Question 37

-1 ions?

Answer 37

F,Cl,Br,I

Question 38

Mono atomic ions can have characteristic multiple charge.

Question 39

Ionic compounds.

Answer 39

Charged particles never found alone, always paired with oppositely charged particles.
Combine ions with opposite charge to cancel overall charge to write ionic formulas.

Question 40

Polyatomic ions.

Answer 40

A group of atoms that is covalently bonded AND has a charge.
Aka molecular ion
Frequently in parentheses.