Atomic structure and bonding (2) ✅ Flashcards
atom created/destroyed, diff e = diff p, all elements r made up of..
What did John Dalton do?
-all elements are made up of small indivisible particles called atoms
-atoms cannot be created or destroyed
-atoms of different elements have different properties
electron, pp model, atom neutral because has equal numbers of p+…
what did j.j thompson do?
-discovered the electron
-proposed the plum pudding model
-suggested atom was neutral as it contained equal number of protons and electrons
what is the plum pudding model
negative electrons embedded into a sphere of positive charge
atom consisted of, named positive particles …
what did ernest rutherford do?
-proved that atoms consisted of electrons revolving around positively charged nucleus
-called the positive particles protons
showed n of atom had two diff,named neutral particles,why hard find
what did james chadwick do?
-showed the nucleus of the atom contained two different types of particles
-neutral particles are called neutrons
-they were difficult to detect because it had no charge
what is the relative mass of a proton
1
what is the relative mass of a neutron
1
what is the relative mass of an electron
1/1840
what is the relative charge of a proton
+1
what is the relative charge of a neutron
0
what is the relative charge of an electron
-1
where is the proton found
in the nucleus
where is the neutron found
in the nucleus
where is the electron found
in the shell
what is the atomic number
number of protons in an atom
what is the mass number
protons + neutrons
equa
why does the atom as a whole have no electrical charge
the number of protons and neutrons are equal so the charges cancel out
what does the group number represent
(the number of _________ in the outer _____)
the number of electrons in the outer shell
what does the period number represent
(number of ______ in use)
number of shells in use
what is the size of an atom
0.1 nanometers
what’s an isotope
atoms of an element with the same atomic number but a different mass number,
therefore a different number of neutrons
what do all noble gasses have
stable full outer shell of electrons
what are ions and how are they formed
charged particles formed when atoms lose or gain electrons to achieve a full outer shell of electrons
if an atom gains an electron does it become positive or negative
negative
what are molecular ions
charged particles containing more than one atom
in this carbonate ion, where is the valency
2-
CO
3
-2
the top one
what is chemical bonding
when an atom doesn’t have a full outer shell, it will want to react with another atom to achieve a full outer shell
Maybe Cillian Isn’t Brilliant
what are the three types of bonding
Ionic bonding
Covalent
Metallic
ionic bonding is between what two types of elements
metal + non-metal
covalent bonding is between what two types of elements
non-metal + non-metal
metallic bonding is between what two types of elements
metal + metal
when do ionic bonds form
when a metal transfers electrons to a non-metal forming positive and negative ions
where is ionic bonding found
in metal compounds
what is a crystal of sodium chloride held together by?
a giant ionic lattice
physical properties of ionic compounds
high melting/boiling point
soluble in water
DONT HAVE electrical conductivity UNLESS MOLTEN OR DISSOLVED IN WATER
why do substances of ionic compounds have a high melting/boiling point
lots of energy is required to break the STRONG ELECTROSTATIC FORCES OF ATTRACTION as a result ionic substances are solid at room temp and have high b/m point
why do substances of ionic compounds have no electrical conductivity
because there are no charged particles free to move and carry the charge
what is covalent bonding
a covalent bond is a shared pair of electrons the bonds within the molecules are strong and require lots of energy to break them
where is covalent bonds found in
found in non-metallic elements and compounds
what are covalent substances composed of and what are they called and what is their structure described as
small molecules called simple covalent molecules. structure described as molecular covalent
what are the weak intermolecular forces of attraction between the covalent structures molecules called
Van der Waals’ forces
what are the physical properties of molecular covalent structures
low melting/boiling points
don’t conduct electricity
insoluble in water
why do molecular covalent structures have low melting/boiling points
little energy is required to break the weak Van der Waals’ forces of attraction between the molecules
what do molecular covalent structure substances exist as at room temperature
gasses, liquids or low melting point solids
why do molecular covalent structure substances not conduct electricity
they have no charged ions or electrons to move and carry the charge
what are giant covalent structures composed of
covalently bonded atoms
properties of giant covalent structures (2)
high melting/boiling point
insoluble in water
why do giant covalent structures have high melting/boiling points
the many strong covalent bonds between the atoms means a lot of energy is required to break the strong covalent bonds
name a use of diamonds
diamond tipped drills to cut through things like rock, metal and glass
Property of diamond (carbon)
Each carbon atom is covalently bonded to 4 other carbon atoms in what arrangement for diamond?
in a tetrahedral three-dimensional arrangement
Name two properties of diamond other than the arrangement/what its bonded to
doesn’t conduct electricity
high melting point
name two uses of graphite and why graphite is used for them
lubricant for machinery
pencil leads
because layers can slip easily over one another
property of graphite (carbon)
what arrangement are graphite atoms arranged in, and to how many other carbons is it bonded to?
in the hexagonal layers each carbon is bonded to 3 others.
name two other properties of graphite (carbon)
conducts electricity
high melting point
why does graphic (carbon) conduct electricity
the delocalised electrons between layers are free to move and carry charge
what are allotropes, their state
different forms of the same element in the same physical state
name 3 examples of allotropes
Diamond, graphite, graphene - forms of the same element
carbon - same physical state (solid)
what is the arrangement of metallic bonding
regular arrangement of positive ions surrounded by a sea of delocalised electrons
what is the metallic bond
the strong force of attraction between the positive metal ions in a regular lattice and the delocalised electrons
Can Elijah, Make, Dudes, Highs Melt Promptly
Name 3 properties of metals
High melting point
Conduct electricity
Malleable
Ductile
why do metals have a high melting point
a large amount of energy is required to break the strong metallic bonds between the positive ions and the delocalised electrons
all metals are solids, the only exception is m……
mercury
if a metal is solid at room temperature that means it has a high ….
(2)
boiling and melting point
why are metals malleable and ductile?
the layers can slide over
without disrupting the
the ……. is maintained because
after sliding the positive ions settle into their new ……… and what is restored
the layers of ions can slide over each other without disrupting the bonding, the bonding is maintained because the bonds are fixed and not rigid. after sliding the positive ions settle into their new positions and structure is restored
what is an alloy and what is the resulting mixture
mixture of two or more elements one of which is a metal. Resulting mixture has metallic properties
Harry Ellerby-Cant Rest-to-Cry
what are the improved properties of an alloy and an example
(mild steel is an alloy of)
hardness
electrical conductivity
resistance to corrosion
mild steel is an alloy of iron and carbon
how do you work out the percentage of gold in an alloy?
number of carats
————————- X100
24
what is a use of aluminium + why aluminium is used for that
overhead electrical wires
conducts electricity, low density, malleable + ductile
what are 2 uses of magnesium + why magnesium is used for them
flares and airplanes
burns with bright white light, strong, low density
what is a use of iron + why iron is used for them
bridges and structures
strong, relatively cheap
what is a use of copper + why is copper used for it
plumbing applications
doesn’t react with water/steam, malleable, ductile
what is a nanoparticle
a structure 1-100nm in size and contains a few hundred atoms
mass of isotope = moi, abundance = a
how do you work out RAM/AR
(Mass of isotope x abundance)
+
(Mass of isotope X abundance
————————–
Total abundance
does it occur in equal amounts? 75% have mass of, 25% have mass of
why is the mass number of chlorine given as 35.5 in the periodic table if the mass of one isotope is 35 and the other is 37?
Isotopes don’t occur in equal amounts
-75% of chlorine atoms have a mass of 35
-25% of chlorine atoms have a mass of 37
Properties of graphite (carbon)
The hexagonal layers are held together by what + what are they caused by, which can easily …. …. ………
therefore…
The layers are held together by weak forces caused by delocalised electrons which can easily slip over each other. Therefore graphite is a soft substance
