atomic structure

Question 1

what is an atom

Answer 1

the smallest part of an element

Question 2

what are the models in order

Answer 2

Dalton Model, Plum Pudding Model, Rutherford Model, Bohr Model, Quantum Model

Question 3

what is dalton’s atomic theory

Answer 3

• all matter is composed of small particles called atoms which cannot be subdivided, created or destroyed
• atoms of an element are identified in their physical or chemical element
• atoms of different elements differ in their physical or chemical properties
• atoms of different elements combine in simple whole number ratios to form compounds
• in chemical reactions, atoms are combined, separation or rearranged, but never created or destroyed

Question 4

changes to Dalton’s theory

Answer 4

• atoms can be subdivided , created and destroyed ( atomic bomb, man made elements)
• atoms of the same element are NOT identical (isotopes)

Question 5

what does Dalton’s model show

Answer 5

that atoms are tiny particles with no internal structure

Question 6

what is the Plum pudding model

Answer 6

-1904, Thompson disproved Dalton’s model of the atom

Question 7

how did Thompson discover the electron

Answer 7

used a cathode ray tube (CRT)

Question 8

what does the Plum Pudding model show

Answer 8

that negatively charged particles balance the positively charged particles to make atom neutral

Question 9

what is the Rutherford model

Answer 9

in 1911, Rutherford disproved Thompson’s Plum Pudding model

Question 10

how did Rutherford disprove Thompson’s Plum Pudding Model

Answer 10

he shot positively charged particles at a thin foil of god (Gold foil experiemnt)

Question 11

what does the Rutherford model show that

Answer 11

• the nucleus is small and positive because few positively charged particles were deflected
• the electron cloud is large and negative because many positively charged particles penetrated
• most of the mass is in the nucleus
• most of the atom is empty space

Question 12

Bohr model

Answer 12

-in 1913, Bohr said electrons travel around the nucleus in specific energy levels

Question 13

why is the Bohr model incorrect

Answer 13

because it is difficult to pinpoint fast moving electrons

Question 14

what is the quantum model

Answer 14

in 1926 a present day model of the atom shows electrons have wavelike properties and are somewhere in the electron cloud

Question 15

what are the atom parts

Answer 15

the nucleus and electron cloud

Question 16

the nucleus

Answer 16

• in the center
• smallest region
• positively charged
• has most of the mass

Question 17

the electron cloud

Answer 17

• the outer region
• largest region
• negatively charged
• mostly empty space

Question 18

where is proton found

Answer 18

nucleus

Question 19

charge of proton

Answer 19

positive

Question 20

symbols of proton

Answer 20

1+ or +

p+ or p

Question 21

what is the mass of a proton

Answer 21

1.673 x 10-27kg

Question 22

location of neutron

Answer 22

nucleus

Question 23

charge of neutron

Answer 23

no charge

Question 24

symbols for neutron

Answer 24

0 or n

Question 25

mass of neutron

Answer 25

1.675 x 10-27 kg

Question 26

location of electrons

Answer 26

electron cloud

Question 27

charge of electron

Answer 27

negative

Question 28

symbols of electron

Answer 28

1- or -

e- or e

Question 29

mass of electron

Answer 29

9.109 x 10-31kg

Question 30

atomic number

Answer 30

• each element has different atomic number
• elements are arranged according to increasing atomic number
• reveals the number of protons
• also reveals the number of electrons ( if the element is neutral)

Question 31

what is the mass number

Answer 31

sum of the protons and neutrons

round the average atomic mass to a whole number

Question 32

neutron number

Answer 32

neutron number = mass number minus atomic number

Question 33

what is an ion

Answer 33

an atom that gains or loses electrons

Question 34

what is a cation

Answer 34

• an ion with a positive charge

- loses electrons

Question 35

what is a anion

Answer 35

an ion with a negative charge

gains electrons

Question 36

what is an isotope

Answer 36

• all have the same number of protons
• all have the same chemical behavior
• the mass number is different because the umber of neutrons is different

Question 37

how are isotopes written

Answer 37

hydrogen-2

H-2

Question 38

what is the average atomic mass

Answer 38

• decimal # on the periodic table
• it is calculated using all naturally occurring isotopes of an element
• keep all numbers after the decimal
• the unit is amu ( atomic mass unit)

Question 39

what is the percent abundance

Answer 39

occurrence of an isotope in nature
one number after the decimal
the unit is %