atomic structure & the periodic table

Question 1

John Daltons discoveries

Answer 1

• all substances are made of atoms
• atoms of the same element are alike and atoms of different elements are different
• atoms join with other atoms to make new substances

Question 2

John daltons model

Answer 2

solid sphere ball thing

Question 3

JJ Thomson discoveries

Answer 3

• atoms can be divided into smaller parts
• electron beam moved away from the negatively charged plate towards a positively charged plate so he knew that the particles must have a negative charge

Question 4

JJ Thomson model

Answer 4

plum pudding model

Question 5

Ernest Rutherford discoveries

Answer 5

• shot alpha particles into a sheet of gold foil and some went through but some bounced off so he knew atoms were made mostly of empty spaces and electrons travel in random orbits around the nucleus
• most of the mass is in the nucleus

Question 6

Ernest Rutherford model

Answer 6

nuclear model

Question 7

structure of atom

Answer 7

mass in its nucleus, nucleus made up of protons and neutrons, electrons orbit the nucleus in energy shells

Question 8

electrons

Answer 8

negatively charged particles

Question 9

protons

Answer 9

positively charged particles

Question 10

neutrons

Answer 10

neutral charged particles (no charge)

Question 11

alpha particle

Answer 11

particle consisting of 2 protons and 2 neutrons tightly bound together

Question 12

relative charge and relative mass of protons

Answer 12

relative charge: +1
relative mass: 1

Question 13

relative charge and relative mass of neutron

Answer 13

relative charge: 0
relative mass: 1

Question 14

relative charge and relative mass of electron

Answer 14

relative charge: -1
relative mass: 1/1835

Question 15

why do atoms contain equal number of protons and electrons

Answer 15

atoms are neutral so the amount of protons need to cancel out the amount of electrons. thats why theres an equal amount so its balanced

Question 16

mass number

Answer 16

number of protons and neutrons

Question 17

atomic number

Answer 17

number of protons or number of electrons

Question 18

isotopes

Answer 18

different atoms of the same element containing same number of protons but different number of neutrons

Question 19

how to calculate number of neutrons

Answer 19

mass number-atomic number

Question 20

how does the existence of isotopes result in RAM of some elements not being whole numbetd

Answer 20

RAM is calculated using the amount of different isotopes and because it is an average it can lead to the RAM not always being a whole number

Question 21

equation to figure out RAM

Answer 21

(mass of isotope A x % of isotope A) + (mass of isotope B x % of isotope B) / 100

Question 22

how did Mendeleev arrange the elements

Answer 22

based on the order of their atomic mass, but sometimes he changed the order based on atomic weight
he left gaps for undiscovered elements

Question 23

how did he use his table to predict the existence of undiscovered elements

Answer 23

he realized elements with similar properties belonged in the same group so he left gaps for the undiscovered elements to fit in

Question 24

why was mendeleevs order of the elements increasing in RAM not always true

Answer 24

because certain isotopes can change the RAM when taken into account. some elements can have higher ones or lower ones depending on the isotopes taken into account

Question 25

what is meaning of atomic number of an element in terms of position of the element

Answer 25

elements are arranged in order of atomic number (bottom number) and elements with similar properties are in groups. they have the same number of electrons in their outershell.

Question 26

metals

Answer 26

elements that react to form positive ions

Question 27

non metals

Answer 27

elements that do not form positive ions

Question 28

group 1 elements name + properties

Answer 28

alkali metals - soft - relatively low melting points - highly reactive (get more reactive going down)

Question 29

what gas is formed when an alkali metal reacts with water

Answer 29

hydrogen

Question 30

pattern of reactivity in terms of electron configuration for group 1

Answer 30

it gets easier to lose electrons due to the increase in electron shells and harder to form positive ions as u go down. theres a decrease in force of attraction between the positively charged nucleus and negatively charged outershell electron

Question 31

color and physical state of chlorine, bromine, fluorine and iodine

Answer 31

chlorine is a yellow green gas, bromine is a red brown liquid, fluorine is pale yellow gas, iodine is a gray/dark gray solid

Question 32

properties of halogens

Answer 32

- non metals - bad conductors of heat and electricity - brittle when solid - poisonous - highly reactive - melting and boiling point decreases down the group

Question 33

chemical test for chlorine

Answer 33

when damp litmus paper is put into chlorine gas, the litmus paper bleaches and turns white

Question 34

why does reactivity decrease going down group 7

Answer 34

electron shells are added going down the so the force of attraction between the nucleus and outermost shell decreases. makes it harder to form a positive ion so reactivity decreases

Question 35

what do halogens exist as and why

Answer 35

diatomic molecules: all halogens require one more electron to obtain a full outer-shell and become stable so they all have to share 1 electron with another atom to form a single covalent bond

Question 36

what is a redox reaction

Answer 36

when a more reactive halogen displaces a less reactive in an aqueous solution of its salt

Question 37

oxidization

Answer 37

loss of electrons

Question 38

reduction

Answer 38

gain of electron

Question 39

reactivity of halogens in terms of electronic configuration

Answer 39

as you move down group 7, an electron shell is added so the force of reaction decreases between the outermost shell and so does the reactivity

Question 40

group 0/8 name + properties

Answer 40

noble gasses - non reactive - odorless - colorless - stable