C1/Atomic Structure and Periodic Table Flashcards
all substances are made of what?
atoms
true or false?
an atom is the smallest part of an element that can exist
true
atoms of each element are represented by what?
a chemical symbol
approximately how many different elements are found in the periodic table?
100
how are compounds formed?
from elements in chemical reactions
true or false?
chemical reactions always involve the formation of one or more new substances, and often involve a detectable energychange
true
a mixture consists of what?
two or more elements or compounds not chemically combined together
what is a compound?
two or more elements chemically combined in fixed proportions
compounds can only be separated by what?
chemical reations
in a mixture the chemical properties of each substance in the mixture remain what?
unchanged
name five ways mixtures can be separated by physical processes
filtration crystallisation simple distillation fractional distillation chromotography
true or false?
physical processes do involve chemical reactions and new substances are made
false.
physical processes do not involve chemical reactions and no new substances are made
new experimental evidence may lead to what?
a scientific model being changed or replaced
before the discovery of the electron, atoms were thought to be what?
tiny spheres that could not be divided into anything smaller
the discovery of the electron led to which model of atom?
the plum pudding model
the plum pudding model suggested that the atom is a ball of positive charge with negative electrons located where?
embedded everywhere in it
the results from the alpha particle scattering experiment led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was what?
positively charged
the nuclear model replaced what?
the plum pudding model
Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus in what?
shells
later experiments led to the idea of which particle?
the positively charged proton
the experimental work of James Chadwick provided the evidence to show the existence of which particles within the nucleus?
neutrons
protons have what charge?
positive
neutrons have what charge?
neutral
electrons have what charge?
negative
in an atom, the number of electrons is equal to the number of what?
protons
what is the charge of an atom?
zero
what is the atomic number?
the number of protons
how big are atoms?
they are very small
approximately how big is the radius of an atom?
0.1nm (1x10-10m)
where is the most mass of an atom?
in the nucleus
the relative mass of a proton is what?
1
the relative mass of a neutron is what?
1
the relative mass of an electron is what?
very small or 0
what is the mass number?
the number of protons+neutrons
what are the atoms of the same element with different numbers of neutrons called?
isotopes
how are the electrons arranged on each shell?
2:8:8
the elements in the periodic table are arranged in order of what?
atomic (proton) number
in the periodic table elements with similar properties are in columns known as what?
groups
why do elements in the same group have similar chemical properties?
they have the same number of electrons in their outer shell
before the discovery of protons, neutrons and electrons, scientists attempted to classify the elements by arranging them in order of what?
their atomic weights
true or false?
the early periodic tables were incomplete and some elements were placed in inappropriate groups if the strict order of atomic weights was followed
true
Mendeleev overcome some of the problems with the early periodic table, what were they?
he left gaps in the periodic table for elements that he thought had not been discovered
he changed the order of elements based on atomic weights
elements with properties predicted by Mendeleev were what?
discovered and used to fill gaps in his periodic table
isotopes are are atoms of the same element with a different number of which particle?
neutrons
metals react to form what type of ions?
positive
non-metals react to what type of ions?
negative
the majority of elements are what?
metals
metals are found where in the periodic table?
left and towards the bottom of the periodic table
non-metals are found where in the periodic table?
towards the right and top of the periodic table
the elements in group 0 of the periodic table are called what?
the noble gases
the elements in group 0 are un-reactive and do not easily form molecules because their atoms have what?
a full outer shell of electrons
true or false?
the boiling points of the noble gases decrease with increasing relative atomic mass (as you go down the group)
false.
the boiling points of the noble gases increase with increasing relative atomic mass (as you go down the group)
the elements in group 1 of the periodic table are known as what?
the alkali metals
why do group 1 elements have similar properties?
they have one electron in their outer shell
true or false?
in group 1 the reactivity of the elements increase going down the group?
true
the elements in group 7 of the periodic table are known as what?
halogens
why do group 7 elements have similar properties?
they have seven electrons in their outer shell
are the halogen metals or non-metals?
non-metals
the halogens are molecules that have how many atoms?
they exist as pairs of atoms
as you go down group 7 name three things that increase?
the mass of the element
the melting point of the element
the boiling point of the element
true or false?
as you go down group 7 the reactivity of the elements increases
false.
as you go down group 7 the reactivity of the elements decreases
a more reactive halogen can displace what?
a less reactive halogen from its salts
the transition elements are found where in the periodic table?
the middle
name 6 transitions metals
Cr, Mn, Fe, Co, Ni, Cu
the properties of the transition metals are different from those of the elements in which group?
group 1
many transition elements often form what?
coloured compound
many transition elements are often used as what?
catalysts
iron is a catalyst in which process?
haber process
nickle is a catalyst in which process?
margarine production
