Atomic Structure & Nucleus

Question 1

What occupies most of the atoms volume?

Answer 1

Electrons

Question 2

what subatomic particle has the most mass?

Answer 2

Neutrons
protons
electrons

Question 3

What is atomic number?

Answer 3

It is the number of protons and electrons
p=e

Question 4

How to find the number of neutrons?

Answer 4

Mass no - atomic no

Question 5

What are isotopes?

Answer 5

Atoms with the same number of Protons but different number of neutrons
They have the same atomic number(small) but different mass number(big)

Question 6

How are isotopes written?

Answer 6

Symbol and mass number at the top

Question 7

What are ions?

Answer 7

Atoms become ions after gaining or losing an electron

Question 8

cations

Answer 8

are positive
Loss of electron happened

Question 9

anions

Answer 9

are negative
gain of e happened

Question 10

Where do we put the electrons for cation and anion equations?

Answer 10

cation: put in products (Na = Na + e)
anion: put in reactants (O +2e = O)

Question 11

How to find the atomic mass of an isotope?

Answer 11

Sum of (% of isotope x mass of isotope)

Question 12

how are isotopes of atoms determined?

Answer 12

mass spectrometer (IADD)
Ionization (sample is already)
acceleration (through electromagnet)
deflection (circular path)
detection (on plate)

Question 13

What does Dalton’s hypothesis for constant mass explain?

Answer 13

Naturally a green samples of an element have almost the same mixture of isotopes

Question 14

how are artificial elements different from natural element in terms of atomic mass and atomic number?

Answer 14

Artificial elements have atomic number greater than 92 & don’t have an atomic mass

Question 15

what is the value of the fundamental unit of charge

Answer 15

1.6 x 10^-19 C

Question 16

What subatomic particle uniquely identifies an element?

Answer 16

Proton

Question 17

what is the energy level of the electrons that are closer to the nucleus?

Answer 17

They are at lower energy level

Question 18

Name the 3 isotopes of Hydrogen.

Answer 18

Atomic mass 1 amu = protium
2 amu = deuterium
3 amu = tritium

Question 19

atomic weight

Answer 19

Weighted average of different isotopes
number on the periodic table
Corresponds with mass number

Question 20

What is a mole and what is it equals to?

Answer 20

Atoms, ions, molecules
6.02 x 10^23

Question 21

Binding energy

Answer 21

Energy required to separate components an atom

Question 22

mass defect

Answer 22

When the nucleus has less mass than the sum of Protons and neutrons

Question 23

nucleon

Answer 23

collective term for protons and neutrons

Question 24

How is binding energy measured

Answer 24

Per nucleon

Question 25

what is the formula for binding energy

Answer 25

E = mc^2 c = 3 x 10^8

Question 26

How to convert u to kg

Answer 26

/6.022*10^23 / 1000

Question 27

Nuclear transmutation

Answer 27

When nuclear changes changes the number of protons

Question 28

Radioactive/nuclear decay

Answer 28

When naturally occurring isotopes of some elements get rid of their protons or neutrons to become stable

Question 29

Why are isotopes radioactive?

Answer 29

Because they emit nuclear radiation

Question 30

Name nuclear radiation types

Answer 30

Alpha particles Beta particles Positrons Gamma radiation

Question 31

What are alpha particles made up of and which element are they associated with

Answer 31

2p + 2n He - 4 (of periodic table)

Question 32

What are beta particles?

Answer 32

They are electrons with extremely high energies

Question 33

What are positrons?

Answer 33

They are similar to beta particles with positive charges

Question 34

photons

Answer 34

electromagnetic packets of light

Question 35

What are gamma particles?

Answer 35

photons of EM radiation

Question 36

nuclide

Answer 36

nucleus of the isotope

Question 37

parent nuclide

Answer 37

nuclide that undergoes radioactive decay is

Question 38

daughter nuclide

Answer 38

nuclide that is produced

Question 39

what is the mass number of beta and positron?

Answer 39

0

Question 40

positron emission / beta plus decay

Answer 40

Type of beta decay in which emitted particle is a positron

Question 41

positron

Answer 41

antimatter equivalent of an electron with positive charge

Question 42

Electron capture

Answer 42

One of the electrons closer to the nucleus are pulled in and a proton is converted to a neutron

Question 43

Radioactive series

Answer 43

When a radioactive isotope decays and produces another radioactive isotope which further decays

Question 44

Disintegration

Answer 44

Each particle's emission

Question 45

Activity (A) How is activity of a sample measured

Answer 45

Rate of decay Can be measured in the number of disintegrations per unit time

Question 46

Geiger counter

Answer 46

A device that can detect radioactive disintegrations

Question 47

why is I-123 used instead of I-131?

Answer 47

I-131 is carcinogenic

Question 48

Why are radioactive isotopes used as tracers to determine the activity of the non radioactive isotope?

Answer 48

Both of them undergo the same chemical reactions non radioactive isotopes cannot be traced

Question 49

Strong nuclear force

Answer 49

attractive force that all nucleons exert on other nucleons to keep the nucleus from flying apart

Question 50

Magic numbers

Answer 50

Number of protons within a nucleus that make it more stable