atoms and the periodic table

Question 1

what do the rows tell you in the periodic table?

Answer 1

elements in the same row have the same number of occupied elctron shells

Question 2

what do groups tell you

Answer 2

elements in the same group have the same number of electrons in their outer shells

Question 3

how are the elements arranged in the modern periodic table?

Answer 3

they are arranged by atomic number

Question 4

who first organised the periodic table?

Answer 4

john newlands

Question 5

how did john newlands first organize and what did he notice about the periodic table?

Answer 5

he ordered them using the atomic masses and he noticed a pattern which he called octaves where each element was similar to the one eight places ahead of it

Question 6

what were the problems with john newlands table?

Answer 6

many of his atomic weights were not accurate
he sometimes would put two elements in the same box when convienient
some elements in an octave had very different properties
no spaces for undiscovered elements

Question 7

who ordered the table after john newlands more succesfully?

Answer 7

dmitri mendeleev

Question 8

how did dmitri mendeleev organize the periodic table?

Answer 8

organized them by the atomic weights and properties

Question 9

why was dmitri menedleev table so much better than john newlands/

Answer 9

he recallculated the atomic weights
he left gaps for undiscovered elements and predicted their properties
rearranged the table so elements with similar properties fell into groups

Question 10

how is the modern periodic table arranged?

Answer 10

by electronic structure

Question 11

how does the modern periodic table differ from mendeleevs?

Answer 11

details such as how many electrons protons and neutrons
mendeleev had no knowledge of subatomic particles

Question 12

give an everyday example of an exothermic reaction

Answer 12

hand warmers, self heating can

Question 13

give an everyday example of an endothermic reaction

Answer 13

cold pack

Question 14

what is activation energy?

Answer 14

the amount of energy needed to get a reaction started
this energy is needed to break bonds so new ones can form

Question 15

what would an exothermic reaction diagram look like?

Answer 15

the energy needed to break bonds is less than the energy released forming new bonds

           \_\_\_\_ e l         /        \ n l \_\_\_\_/           \ e l                      \ r l                         \\_\_\_\_\_\_ g l y l\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
   time

Question 16

describe the energy changes in a reaction

Answer 16

energy is needed to break bonds
energy is released when bonds are made

Question 17

what does an endothermic reaction diagram look like?

Answer 17

the energy needed to break bonds is more than the energy released from forming bonds

e l ____
n l / \
e l / \_____
r l /
g l ____/
y l__________________

Question 18

whats the equation for calculating the energy transfer/change?

Answer 18

energy transfer= energy taken to break bonds-energy released making bonds

Question 19

how can we increase the rate of reaction

Answer 19

by increasing the amount of reactant we are putting in. This means their are more particles so their will be more collisions so will increase the rate of reaction

Question 20

how do catalysts work?

Answer 20

they provide an easier path for the chemical reaction that provides less activation energy

Question 21

describe an isotope

Answer 21

has the same atomic structure but different number of neutrons

Question 22

how do you calculate the relative atomic mass of two isotopes?

Answer 22

relative atomic mass= (atomic mass of isotope 1 x abundance of isotope 1)+(atomic mass of isotope 2 x abundance of isotope 2)
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