atoms and elements

Question 1

what is an atom

Answer 1

an atom is the smallest unit of matter but still has the properties of an element

Question 2

what is an atom made of

Answer 2

3 sub-atomic particles called protons, neutrons and electrons

Question 3

what is the charge of protons, neutrons and electrons

Answer 3

protons +1, neutrons 0, electrons -1

Question 4

what is the mass of protons, neutrons, electrons

Answer 4

protons 1, neutrons 1, electrons 1/1837

Question 5

where are protons, neutrons and electrons located

Answer 5

protons and neutrons are in the nucleus and electrons surround the nucleus

Question 6

what is another unit for atomic mass unit (amu)

Answer 6

dalton

Question 7

describe the mass of protons and neutrons

Answer 7

they have an identical mass of 1.7x10-24 g

Question 8

what is the mass of a proton and neutron

Answer 8

1 dalton

Question 9

what are the two models called

Answer 9

planetary model (bohr model) and electron cloud model schrodinger

Question 10

when was the planetary model made

Answer 10

1913

Question 11

when was the electron cloud model made

Answer 11

1926

Question 12

describe the electron cloud model

Answer 12

represents the two electrons as a cloud of negative charge

Question 13

describe the planetary model

Answer 13

the electrons are shown as two spheres on a circle around the nucleus

Question 14

what is mass number

Answer 14

number of protons + number of neutrons

Question 15

what does a proton determine

Answer 15

an element

Question 16

what does a neutron determine

Answer 16

an isotope

Question 17

what is an isotope

Answer 17

a different atomic form of the same element but with different number of neutrons but same number of protons

Question 18

what is ground state

Answer 18

when the distance between the electron and proton is smaller (than excited state)

Question 19

what is the excited state

Answer 19

when the distance between the electron and proton is larger (than ground state)

Question 20

what is the atomic number

Answer 20

sum of protons

Question 21

what is an element

Answer 21

a substance that can’t be broken down to any other substances by chemical reactions

Question 22

what is sodium used for

Answer 22

salt, streetlights, in our bodies (for muscles)

Question 23

what is chlorine used for

Answer 23

toxic gas, water treatment, pvc (plastic)

Question 24

what is a compound

Answer 24

a substance that consists of two or more different elements combined

Question 25

what is an example of a compound

Answer 25

water ( 2H2 + O2= 2H2O)

Question 26

is the atomic number the bottom or top number

Answer 26

top number

Question 27

is the atomic mass the bottom of top number

Answer 27

bottom number

Question 28

what is an example of an isotope

Answer 28

carbon= 12C (6 protons), 13C (7 p) and 14C (8 p)

Question 29

do isotopes behave the same or different in chemical reactions

Answer 29

the same

Question 30

why are 12C and 13 C (isotopes) more stable than 14C

Answer 30

because the more neutrons you have the more unstable and radioactive the isotope

Question 31

what happens to the stability and radioactivity of the isotope when the number of neutrons increases

Answer 31

stability decreases and radioactivity increases

Question 32

what is a radioactive isotope

Answer 32

when a nucleus decays spontaneously which gives off energy and particles

Question 33

what is radioactive decay

Answer 33

a change in the number of protons

Question 34

what does radioactive decay cause

Answer 34

causes the atom to transform into an atom of a different element

Question 35

are atomic masses always whole numbers

Answer 35

no they may be integers

Question 36

what is the atomic mass of isotopes

Answer 36

the average of the different isotopes

Question 37

what are the types of radioactive decay

Answer 37

- alpha decay - beta decay - gamma decay

Question 38

what is alpha decay

Answer 38

is when the nucleus loses 2 protons

Question 39

what is beta decay

Answer 39

when the nucleus either loses or gains a proton

Question 40

what is gamma decay

Answer 40

when the number of protons doesn't change so there isn't a change in element

Question 41

what can radioactive isotopes be used as in medicine

Answer 41

diagnostic tools

Question 42

what are radioactive tracers

Answer 42

they are radioactive isotopes that are combined into biologically active molecules which are then used to track atoms during metabolism

Question 43

what are radioactive tracers also combined with

Answer 43

PET scanners to monitor growth and metabolism of cancers

Question 44

what happens with energy as we move further away from the nucleus

Answer 44

energy increases

Question 45

describe the energy of the outer shell

Answer 45

has the highest energy

Question 46

describe the reactivity of an atom with full shell

Answer 46

unreactive

Question 47

what is valence

Answer 47

- bonding capacity of an atom - number of covalent bonds the atom can form (equal to number of unpaired electrons on outer shell)

Question 48

what is valence electron

Answer 48

an electron in outer shell

Question 49

what's valence shell

Answer 49

the outer shell with most energy and with valence electron

Question 50

what are 3 ways of showing electron configuration

Answer 50

- electron distribution diagram - superimposed orbitals - separate electron orbitals

Question 51

what is chemical behaviour based on

Answer 51

the number of electrons on it's outer shell

Question 52

describe the chemical beh of atoms with same number of outer electrons

Answer 52

similar chemical behaviour

Question 53

what are types of bonds

Answer 53

- covalent bonds - ionic bonds - electronegativity

Question 54

what is a covalent bond

Answer 54

- a shared pair of electrons - strongest bond

Question 55

what are examples of covalent bonds

Answer 55

- hydrogen - oxygen -water -methane

Question 56

what is electronegativity

Answer 56

attraction of an atom to electrons of a covalent bond

Question 57

what is a non-polar covalent bond

Answer 57

a covalent bond where the two atoms have similar electronegativity

Question 58

what is a polar covalent bond

Answer 58

a covalent bond between atoms that have different electronegativity

Question 59

what happens to the electrons in a polar covalent bond

Answer 59

the electrons are pulled closer to the more electronegative atom (delta negative and other delta positive)

Question 60

what is an ion

Answer 60

an atom that has gained or lost an electron so has gained a charge

Question 61

what is a cation

Answer 61

a positively charged ion (lost an electron)

Question 62

what is an anion

Answer 62

a negatively charged ion (gained an electron)

Question 63

what is an ionic bond

Answer 63

a chemical bond from an attraction between oppositely charged ions

Question 64

name weak chemical interactions

Answer 64

- hydrogen bonds - van der walls

Question 65

what is a hydrogen bond

Answer 65

a weak chemical bond where a partially positive hydrogen atom is attracted to a partially negative hydrogen atom from a different polar bond

Question 66

when was van der waals discovered

Answer 66

1873

Question 67

where do van der walls exist

Answer 67

solids, liquids, gases

Question 68

what are the tree types of van der waals

Answer 68

- dipole induced dipole - dipole dipole (strongest type) - london dispersion forces

Question 69

what is a dipole

Answer 69

a set of separated charges in an atom

Question 70

what is a dipole dipole

Answer 70

is an attraction between 2 polar molecules

Question 71

what is a dipole induced dipole

Answer 71

an attraction between a polar molecule and an atom with an induced dipole

Question 72

what is a london dispersion force

Answer 72

an attraction between a nonpolar atom with an instantaneous dipole and a nonpolar atom with an induced dipole