Chapter 4 - Chemical Foundations: Elements, Atoms, and Ions

Question 1

What are the 2 applications of chemistry that were used before 1000 BC?

Answer 1

the processing of ores to produce metals for ornaments and tools and the use of embalming fluids

Question 2

What were the four fundamental substances that the Greeks had proposed matter to have composed of in 400 BC?

Answer 2

fire, earth, water, and air

Question 3

Some alchemists were what?

Answer 3

mystics and fakes who were obsessed with the idea of turning cheap metals into gold

Question 4

Which elements were found by alchemists?

Answer 4

mercury, sulfur, and antimony

Question 5

What did alchemists learn how to do?

Answer 5

to prepare acids

Question 6

Who was the first scientist to recognize the importance of careful measurements?

Answer 6

Robert Boyle (1627-1691)

Question 7

What was Boyle’s most important contribution to science?

Answer 7

his insistence that science should be firmly grounded in experiments (his definition of element was based on experiments)

Question 8

Why couldn’t air be considered an element?

Answer 8

because it could be broken down into many pure substances

Question 9

All matter can be broken down chemically into about how many different elements?

Answer 9

100

Question 10

How many different elements are known? And how many of those occur naturally?

Answer 10

115; 88

Question 11

What are the 5 most abundant elements in the Earth’s crust, oceans and atmosphere? (List in order of abundance)

Answer 11

Oxygen (49.2%), silicon (25.7%), aluminum (7.50%), iron (4.71%), calcium (3.39%)

Question 12

What are the elements that are the basis for all biologically important molecules?

Answer 12

Oxygen, carbon, hydrogen, and nitrogen

Question 13

What are trace elements?

Answer 13

elements found in the body that are crucial despite their small amounts

Question 14

how many known substances are composed of elements?

Answer 14

millions

Question 15

What is the microscopic form of an element?

Answer 15

the single atom of the element

Question 16

What is the macroscopic form of an element?

Answer 16

a sample of the element large enough to weigh on a balance

Question 17

What does the law of constant composition state?

Answer 17

a given compound always has the same composition regardless of where it comes from

Question 18

State Dalton’s atomic theory (1808)

Answer 18

1) elements are made of tiny particles called atoms
2) all atoms of a given element are identical
3) the atoms of a given element are different from those of any other element
4) atoms of one element can combine with atoms of other elements to form compounds. A given compound always has the same relative numbers and types of atoms
5) atoms are indivisible in chemical processes. Atoms are not created or destroyed in chemical reactions. A chemical reaction simply changes the way the atoms are grouped together

Question 19

Who was J.J. Thomson?

Answer 19

showed that all types of atoms must contain negative particles or electrons; he also concluded that atoms contained positively charged particles to balance the electrons

Question 20

Who was William Thomson or Lord Kelvin?

Answer 20

introduced the plum-pudding model of an atom

Question 21

Who was Ernest Rutherford?

Answer 21

introduced the idea of a nuclear atom, contrary to the plum pudding model

Question 22

What is a nuclear atom?

Answer 22

atom with a dense center of positive charge (nucleus) surrounded by tiny electrons moving in empty space

Question 23

When did Rutherford conclude that the nucleus of the atom contained protons?

Answer 23

1919

Question 24

Who showed that nuclei contained neutrons?

Answer 24

Rutherford and James Chadwick (1932)

Question 25

What is the diameter of the nucleus of an atom?

Answer 25

10^ -13 cm

Question 26

What is the average distance of electrons from the nucleus?

Answer 26

10^ -8 cm

Question 27

The proton’s positive charge is equal to what?

Answer 27

the negative charge of the electrons

Question 28

Why do different atoms have different chemical properties?

Answer 28

the number and arrangement of electrons

Question 29

What accounts for most of the atomic volume?

Answer 29

The space in which the electrons move

Question 30

Which subatomic particle is in charge of intermingling when atoms combine to form molecules?

Answer 30

electrons

Question 31

The number of what greatly affects the way elements can interact with other atoms?

Answer 31

electrons

Question 32

What determines the atom’s chemical behavior?

Answer 32

the number of electrons

Question 33

The number of protons is always equal to the number of electrons. True or false?

Answer 33

true

Question 34

What are isotopes?

Answer 34

atoms with the same number of protons but different number of neutrons

Question 35

what is the atomic number?

Answer 35

The number of protons

Question 36

What is the mass number?

Answer 36

the sum of the number of neutrons and protons

Question 37

A free atom has what charge?

Answer 37

a net zero charge

Question 38

What is chemistry?

Answer 38

The study of matter and how it reacts

Question 39

What is a chemical?

Answer 39

A substance with known composition

Question 40

What is the average atomic mass?

Answer 40

The average of all the mass of the given element

Question 41

1 mole=

Answer 41

6.022*10^23 (atoms, molecules, units)

Question 42

1 mole=what part of the periodic table?

Answer 42

The average atomic mass (g)