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Flashcards in chem chapter 3 test Deck (46):
0

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

properties

1

first to organize elements into a table was ____
how were (are) they organized

Dmitrie Mendeleev
increasing atomic mass

2

periods(rows) are _____ and there are ___ of them
groups(columns) are ____ and there are ____ of them

horizontal, 7
vertical, 18

3

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

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

4

what is the smallest particle of an element

atom

5

who was the first to suggest that atoms existed
who developed the scientific theory behind atoms

democritus, dalton

6

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

false

7

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

true

8

who conducted the gold fold experiment to discover protons

Rutherford

9

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

proton

10

no charge, 1 amu, within the nucleus

neutron

11

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

electron

12

who used the cathode ray tube to discover electrons' charge

JJ Thomson

13

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

nucleus, positively, mass

14

atoms of the same element that have a different mass number

isotope

15

mass number= ___+____

protons+, neutrons0

16

an isotope has __________ atomic mass

whole number

17

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

energy levels

18

what is a quantum

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

19

80% as a decimal is ___ with ____ sig figs

.8, 1

20

molar mass is measured in___
molecular mass is measure in ____

grams, amus

21

how would you find the molar mass of H2SO4

2(1.0)+32.1+64.0=98.1g
(find the elements' masses and add up)

22

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

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

23

how many protons are in 12C
electrons?, neutrons?

6,6,6

24

the number of ____ in an element will never change

protons

25

all carbon atoms have __ protons

6

26

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

1 electron

27

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

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

28

what feature distinguishes a neutral atoms from an ion

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

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

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

30

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

less

31

uranium has 92 protons and 145 neutrons. write its symbol

237
U
92

32

A
X
Z
what does each represent

a-mass number
x-nuclide
z-atomic number

33

all elements have _______ isotopes

at least one

34

% composition=

massX/total mass x 100%

35

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

10% error
99.9%, 100.1%

36

the mass of a mole=formula mass expressed in ___

grams

37

there are 22.4 L/

mole

38

there are _______ particles per mol
what particles are acceptable here and what is this number called

6.022 x 10^23
atoms, molecules, formula units, Avogadro's number

39

every mole of something equals its formula mass of___

grams

40

.8%==

.008

41

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

Different, same

42

What is Cu?

Copper-64

43

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

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

44

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

Tens, hundreds, ones, tenths

45

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

average atomic mass