Atomic structure and the periodic table

Question 1

What is an isotope

Answer 1

isotopes are different forms of the same element, which have the same number of protons but different number of neutrons

Question 2

How were elements arranged in the first periodic tables

Answer 2

By relative atomic mass

Question 3

True or false
Mendeleev considered the properties of isotopes when constructing his periodic table

Answer 3

False
The existence of isotopes wasn’t discovered until later

Question 4

what is the name for the vertical columns in the periodic table

Answer 4

groups

Question 5

true or false
electrons were discovered before protons or neutrons

Answer 5

true
the discovery of the electron led to the plum pudding model

Question 6

what was the plum pudding model of the atom

Answer 6

the plum pudding model described atoms as balls of positive charge with electrons stuck in them

Question 7

which model replaced the plum pudding model

Answer 7

the nuclear model

Question 8

how were alpha particles used to disprove the plum pudding model

Answer 8

alpha particles were fired at a thin sheet of gold. most of the particles went straight through the sheet, but some were deflected more than expected and a small number were even deflected backwards. this meant that the positive charge couldn’t be spread out evenly within the atoms, as described by the plum pudding model

Question 9

how did James Chadwick contribute towards our understanding of the atom

Answer 9

he provided evidence for the existence of neutrons within the nuclei of atoms

Question 10

what did Niels Bohr suggest about the arrangement and movement of electrons in an an atom

Answer 10

he suggested that electrons orbit the nucleus in shells that are a fixed distance from the nucleus. his theory stated that the electrons can only be found in these shells.

Question 11

what are the elements in group 1 more commonly known as

Answer 11

alkali metals

Question 12

true or false
group 1 metals are soft

Answer 12

true
alkali metals are soft with low density

Question 13

why do elements in group 1 share similar properties

Answer 13

all elements in group 1 have one electron in their outer shell so they all form 1+ ions, giving them similar properties

Question 14

how many electrons does helium have in its outer shell

Answer 14

helium has 2 electrons in its outer shell

Question 15

how many electrons do the other noble gases, apart from helium, have in their outer shells

Answer 15

the rest of the noble gases have 8 electrons in their outer shells

Question 16

explain why the noble gases are inert (don’t react)

Answer 16

the noble gases are inert because they have full outer shells, so don’t need to lose or gain any electrons to become stable

Question 17

what sort of compound do halogens form with other non-metals

Answer 17

halogens react with other non-metals to form simple molecular compounds. these compounds contain covalent bonds (shared pairs of electrons)

Question 18

what is the charge on a halide ion

Answer 18

halogen atoms need to gain one electron to complete their outer shell. so they form 1- ions

Question 19

describe the trend in reactivity down group 7

Answer 19

the reactivity of the halogens decreases as you go down group 7, because the outer shell becomes further from the nucleus, so their is less attraction and it is harder to gain an electron