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Flashcards in chem chapter 3 test Deck (46)
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0
Q
first to organize elements into a table was \_\_\_\_
how were (are) they organized
A

Dmitrie Mendeleev

increasing atomic mass

1
Q

Chemists have always used the _____ of the elements to sort them out

A

properties

2
Q

periods(rows) are _____ and there are ___ of them

groups(columns) are ____ and there are ____ of them

A

horizontal, 7

vertical, 18

3
Q

what are the 4 organizational patterns to the modern day period table

A

increasing atomic number, metals nonmetals and metalloids, periods and groups, blocks (spdf)

4
Q

what is the smallest particle of an element

A

atom

5
Q

who was the first to suggest that atoms existed

who developed the scientific theory behind atoms

A

democritus, dalton

6
Q

true or false

different atoms can never chemically combine in fixed ratios to form compounds

A

false

7
Q

true or false

atoms can never change their identity during chemical reactions. They can rearrange to form different compounds

A

true

8
Q

who conducted the gold fold experiment to discover protons

A

Rutherford

9
Q

positive charge, 1 amu (atomic mass unit), within the nucleus

A

proton

10
Q

no charge, 1 amu, within the nucleus

A

neutron

11
Q

negative charge, 1/1840th of a proton or neutron, outside the nucleus

A

electron

12
Q

who used the cathode ray tube to discover electrons’ charge

A

JJ Thomson

13
Q

The _______ is the densest part of the atom, _____ charged, and contains most of the ___ of the atom

A

nucleus, positively, mass

14
Q

atoms of the same element that have a different mass number

A

isotope

15
Q

mass number= ___+____

A

protons+, neutrons0

16
Q

an isotope has __________ atomic mass

A

whole number

17
Q

the energy of an electron is determined by _____-distance from the nucleus

A

energy levels

18
Q

what is a quantum

A

fixed amount of energy (each electron is described by 4 quantum numbers)

19
Q

80% as a decimal is ___ with ____ sig figs

A

.8, 1

20
Q

molar mass is measured in___

molecular mass is measure in ____

A

grams, amus

21
Q

how would you find the molar mass of H2SO4

A

2(1.0)+32.1+64.0=98.1g

find the elements’ masses and add up

22
Q

how do you find percent abundance of an element in a compound

A

put the molar mass of the element over the total molar mass of the compound. divide and multiply by 100

23
Q

how many protons are in 12C

electrons?, neutrons?

A

6,6,6

24
Q

the number of ____ in an element will never change

A

protons

25
Q

all carbon atoms have __ protons

A

6

26
Q

what do all hydrogen atoms (and ions) have in common

A

1 electron

27
Q

what is the significance of the atomic number Z above each element in the periodic table

A

it’s the number of protons in the nucleus of that element

28
Q

what feature distinguishes a neutral atoms from an ion

A

an ion is charged and has an unequal amount of protons and electrons. Atoms are neutral and have an equal amount of protons and neutrons

29
Q

why is most of the mass of an atom within the nucleus

A

it has protons and neutrons while the outside only has electrons and free space

30
Q

in large atoms the number of protons is ____ than the number of neutrons

A

less

31
Q

uranium has 92 protons and 145 neutrons. write its symbol

A

237
U
92

32
Q

A
X
Z
what does each represent

A

a-mass number
x-nuclide
z-atomic number

33
Q

all elements have _______ isotopes

A

at least one

34
Q

% composition=

A

massX/total mass x 100%

35
Q

what error margin is acceptable

when adding percent compositions, what values besides 100% are acceptable?

A

10% error

99.9%, 100.1%

36
Q

the mass of a mole=formula mass expressed in ___

A

grams

37
Q

there are 22.4 L/

A

mole

38
Q

there are _______ particles per mol

what particles are acceptable here and what is this number called

A

6.022 x 10^23

atoms, molecules, formula units, Avogadro’s number

39
Q

every mole of something equals its formula mass of___

A

grams

40
Q

.8%==

A

.008

41
Q

Isotopes have ________ mass numbers (or, number of neutrons) but the __________ atomic number (number of protons)

A

Different, same

42
Q

What is Cu?

A

Copper-64

43
Q

How would you figure out how many H Atoms are in C12H22O11

A

Find out how many molecules total this is and multiply by 22

44
Q
127.5
What place is the 2 in?
1?
7?
5?
(Make sure you remember this in your answer with sig figs
A

Tens, hundreds, ones, tenths

45
Q

The __________ of an element is the weighted average of the masses of the isotopes of that element

A

average atomic mass