Chemistry: Chapter 7 Flashcards Preview

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Flashcards in Chemistry: Chapter 7 Deck (76):
1

valence electron

electrons in the highest energy level of an element's atoms

2

cations

positively charged; loses valence electrons

3

anions

negatively charged; gains valence electrons

4

how to find the number of valence electrons in an element?

look at its group number

5

electron dot structure

diagrams that show valence electrons for atoms of an element as dots

5

electron dot structure

diagrams that show valence electrons for atoms of an element as dots

6

the octet rule

states that in forming compounds, atoms tend to achieve the electron configuration of a noble gas (8 valence electrons)

6

the octet rule

states that in forming compounds, atoms tend to achieve the electron configuration of a noble gas (8 valence electrons)

7

metals....

tend to lose valence electrons (+ charge)

8

non metals...

tend to gain valence electrons (- charge)

9

sodium...= (2)

non reactive; stable in water

10

transition metals....

silver = example

look at last two thingies of a transition metal's electron configuration and determine how many valence electrons it would take to get to 8.

ex. Silver - 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s1 <-- either lose 11, or gain 7!!!!

11

what does an anion's name end with?

-ide

ex. Na + Cl = sodium chlorIDE

12

Halide ions

ions produced when atoms of chlorine and other halogens GAIN electrons

13

ionic compound

compound composed of cations and anions

13

ionic compound

compound composed of cations and anions

14

what is the charge of an ionic compound?

electrically neutral, b/c the charge of the cations are equal to the charge of anions

14

what is the charge of an ionic compound?

electrically neutral, b/c the charge of the cations are equal to the charge of anions

15

ionic bonds

the electrostatic forces that hold ions together in ionic compounds

15

ionic bonds

the electrostatic forces that hold ions together in ionic compounds

16

what attracts anions to cations?

electrostatic forces

16

what attracts anions to cations?

electrostatic forces

17

chemical formula

shows the numbers of atoms of each element in the smallest representative unit of a substance

Ex. Sodium chloride = NaCl

18

formula unit

the lowest whole-number ratio of ions in an ionic compound

18

formula unit

the lowest whole-number ratio of ions in an ionic compound

19

3 properties of ionic compounds?

1. they are crystalline solids at room temperature
2. high melting points
3. can conduct an electric current when melted or dissolved in water

20

coordination number

the number of ions of opposite charge that surround the ion in a crystal

20

coordination number***

the number of ions of opposite charge that surround the ion in a crystal

21

metallic bond

the forces of attraction between the free floating valence electrons and the positively charged metal ions

22

how can you model the valence electrons of metal atoms?

as a sea of electrons

23

properties of metals (3)

good conductors of electric current - b/c electrons can flow freely in the metal

ductile and malleable - b/c of the mobility of valence electrons

if an ionic crystal is struck with a hammer, positive with be pushed together (since they repel each other, the crystal would shatter)

24

describe the crystalline structure of a metal

they are arranged in very compact and orderly patterns

for spheres of identical size, there are many possible arrangements, the three most common ones are body-centered cubic, face-centered cubic, and hexagonal close-packed

24

describe the crystalline structure of a metal

they are arranged in very compact and orderly patterns

for spheres of identical size, there are many possible arrangements, the three most common ones are body-centered cubic, face-centered cubic, and hexagonal close-packed

25

body-centered cubic arrangement (2)

what elements? (4)

every atom, except those on the surface, have 8 neighbors

elements that are in this arrangement: SODIUM, POTASSIUM, IRON, CHROMIUM, AND TUNGSTEN

25

body-centered cubic arrangement (2)

what elements?

every atom, except those on the surface, have 8 neighbors

elements that are in this arrangement: SODIUM, POTASSIUM, IRON, CHROMIUM, AND TUNGSTEN

26

face-centered cubic arrangement (2)

what elements? (5)

every atom has 12 neighbors

elements: COPPER, SILVER, GOLD, ALUMINUM, AND LEAD

26

face-centered cubic arrangement (2)

what elements?

every atom has 12 neighbors

elements: COPPER, SILVER, GOLD, ALUMINUM, AND LEAD

27

hexagonal close-packed arrangement (2)

what elements? (3)

atoms also have 12 neighbors; the difference is the pattern

elements: MAGNESIUM, ZINC, AND CANDIUM

27

hexagonal close-packed arrangement (2)

what elements?

atoms also have 12 neighbors; the difference is the pattern

elements: MAGNESIUM, ZINC, AND CANDIUM

27

alloys

mixtures of two or more elements, at lease one of which is a metal

28

why are alloys important?

b/c their properties are often superior to those of their component elements

29

most important alloys today?

steels

30

principal elements in most steels? (9)

iron, carbon, boron, chromium, manganese, molybdenum, nickel, tungsten, and vanadium.

31

properties of steel?

corrosion resistance

ductile

hardness and toughness

32

substitutional alloy

when atoms of the components in an alloy are about the same size, so they replace each other in the crystal

33

interstitial alloy

if the atomic sizes are quite different, the smaller atoms can fit into the spaces (interstices) between the larger atoms

34

Who developed the octet rule?

Gilbert Lewis

35

steels are what kind of an alloy?

an interstitial alloy

36

steels are what kind of an alloy?

an interstitial alloy

36

How many valence electrons does helium have?

2 valence electrons

37

Non gases are...

Non reactive --> stable

38

Ionization

Process of gaining or losing valence electrons / electrons

39

What is the name of selenium as an anion?

Selenide

40

Describe how ionic compounds conduct electricity

When melted, the crystalline structure breaks down and if a voltage is applied across this melted compound, cations will be free to roam to one electrode to the other and anions migrate to the other. This movement allows an electric current to flow between the electrodes through an external wire

41

What type of alloy is steel?

An Interstitial alloy

41

How do ionic compounds conduct electric current when dissolved in water ?

Same as when the compounds are melted except they are able to migrate around in the solution (water)

42

Metals consist of... (cations and valence electrons)

Closely packed cations and loosely held valence electrons

43

What holds metals together ?

Metallic bonds

44

How do you explain the ductility and malleability of metals?

By the loose mobility of the valence electrons

45

Why are ionic compounds brittle?

Because when it is struck with a hammer in crystalline form, the blow tends to push the positive ions close together and since they repel each other, the crystal shatters

46

How are metals arranged?

In very compact and orderly patterns

47

How do you explain the ductility and malleability of metals?

By the loose mobility of the valence electrons

47

What kind of metals are crystalline? (2)

Metals that contain just one kind of atom

It's the most simple form of all crystalline solids

48

What is brass made up of? (2)

Copper and zinc

49

How are metals arranged?

In very compact and orderly patterns

49

What is Sterling silver made up of? (elements) (2)

Silver and copper

50

What kind of metals are crystalline? (2)

Metals that contain just one kind of atom

It's the most simple form of all crystalline solids

50

Elements that make up bronze? (2)

Copper and tin

51

What alloys make coins? (3)

What are they called? (1)

Bronze, copper-nickel, and aluminum alloys

They are called nonferrous alloys

51

What is brass made up of?

Copper and zinc

52

What elements make up cast iron? (2)

Iron and carbon

53

What elements make up stainless steel ? (3)

Iron

Chromium

Carbon

Nickel

53

Elements that make up bronze?

Copper and tin

54

What alloys make coins?

What are they called?

Bronze, copper-nickel, and aluminum alloys

They are called nonferrous alloys

55

What elements make up cast iron?

Iron and carbon

56

What elements make up stainless steel ?

Iron

Chromium

Carbon

Nickel