Studied by 70 people
What is the definition of isotopes?
atoms of the same element with different number of neutrons
What is the average atomic mass an average of?
average of all naturally existing isotopes of an element
What are the mass of electrons, protons, and neutrons? Write in the format “electrons: X, protons: Y, neutrons: Z)
electrons: 0
protons: 1
neutrons: 1
What does the atomic numbers on the periodic table tell us?
number of protons and electrons
How do you calculate the number of neutrons on a periodic table?
Average atomic mass (rounded) - atomic number (# of protons)
What is the definition of atoms
smallest individual particle of one type of element
Atoms are _______ in charge
neutral
Atoms have the equal number of ______ and _______
protons, electrons
What do you call an atom that gained or lost electron?
ion
What is the definition of ions
an atom or molecule with a net electric charge due to the loss or gain of one or more electrons
What does an atom and an ion of the same element have in common?
same number of protons
What happens when an atom loses an electron and why?
becomes an cation because it is now positively charged
What happens when an atom gains an electron and why?
becomes an anion because it is now negatively charged
Outline what a molecule is and state 3 examples of molecules.
made of 2 or more atoms that are chemically bound (can be same or different elements)
O2, N2, H20 (can be other examples)
Outline what a compound is and state 3 examples of compounds.
made of 2 or more atoms of different elements that are connected by chemical bonds
all compounds are molecules (but not all molecules are compounds)
CO2, NaCl, MgO (can be other examples)
What is the definition of ionic compounds?
two or more ions that form ionic bonds which hold the ions together by the electrostatic forces of attraction
Describe the formation of ionic bonds.
Ionic bonds form between metals and nonmetals when one atom transfers one or more electrons to another atom.
This transfer of electrons creates ions with opposite charges, one positively charged (cation) and one negatively charged (anion).
The electrostatic attraction between these oppositely charged ions forms the ionic bond.
Fill in the blank: Metals are electron _______.
Outline the reason for your answer for the question above.
doners
because metals have lesser than 4 electrons in their valence shells so it is easier for them to donate/lose electrons to form a full valence shell
Fill in the blank: Non-metals are electron _______.
Outline the reason for your answer for the question above.
acceptors
because nonmetals have 4 or more electrons in their valence shells so it is easier for them to gain electrons to form a full octet/valence shell
Outline the trend for the reactivity of metals.
the periodic trend in reactivity of metals increases as you move to the left of the periodic table and down a group
Describe the reason of the periodic trend in reactivity of metals.
Metals with more energy levels have valence electrons that are further away from the nucleus, with weaker attraction.
They lose electrons more easily so they are more reactive as you go down the group.
Metals further to the right in the same period have more protons so there is a stronger attraction for valence electrons.
They lose electrons LESS easily and are LESS reactive.
Outline the trend in reactivity for non-metals.
reactivity increases as you move to the right of the period and up a group
Describe the reason of the periodic trend in reactivity of non-metals.
Non-metals with fewer energy levels have a shorter distance between the nucleus and the valence electrons, with stronger attractive force pulling the electrons
→ They gain electrons more readily and are more reactive as you go up the group
Non-metals further to the LEFT in the same
period have fewer protons so there is a weaker attraction for valence electrons
→ They gain electrons LESS easily and are LESS reactive.
What is the number of the group where Alkali Metals are found on the periodic table?
Group 1
What is the number of the group where Alkaline earth metals are found on the periodic table?
Group 2
What is the number of the group where Halogens are found on the periodic table?
Group 17
What is the number of the group where Noble Gases are found on the periodic table?
Group 18
Why are noble gases not reactive?
Because it has a full valence shell already.
Why are alkali metals very reactive?
Because it only has to lose one electron to have a complete valence shell
Why are halogens very reactive?
because it only has to gain one electron in order to have a full octet
According to the periodic table, state the elements that are a metalloid.
boron, silicon, germanium, arsenic, antimony, tellurium, polonium
or
B, Si, Ge, As, Sb, Te, Po
Who made the solid sphere model? What are the advantages and disadvantages of it?
john dalton 1803
advantages: recognised that atoms of a particular element differ from other elements
disadvantages: atoms are not indivisible, it can be separated
Who made the plum pudding model? What are the advantages and disadvantages of it?
j.j thompson 1904
advantage: recognised electrons as components of atoms
disadvantage: this model does not show the nucleus
Who made the nuclear model? What are the advantages and disadvantages of it?
ernest rutherford 1911
advantage: realised positive charge was localised in the nucleus of an atom
disadvantage: did not explain why electrons remain in orbit around the nucleus
Who made the planetary model? What are the advantages and disadvantages of it?
niels bohr 1913
advantage: proposed stable electron orbits, explained emission spectra for some elements
disadvantage: moving electrons should emit energy and collapse into the nucleus, model did not work well for heavier atom'
Who made the quantum model? What are the advantages of it?
erwin schrodinger 1926
advantage: shows electrons don't move around the nucleus in orbits but in clouds where the position is uncertain, still widely accepted as the most accepted model of the atom
What model did j.j thompson make?
plum pudding model
What model did erwin schrodinger make?
quantum model
What model did Ernest Rutherford make?
nuclear model
What model did niels bohr make?
planetary model
What model did john dalton make?
solid sphere model
State 3 characteristics of metal.
shiny
good conductors of heat and electricity
malleable (able to be hammered or pressed into shape without breaking or cracking)
State 3 characteristics of non-metal.
poor conductors of heat and electricity
not malleable
not ductile (not able to be drawn out into a thin wire)
Heat is released
exothermic
heat is absorbed
endothermic
Electrical Conductivity
Electrical conductivity refers to a
substance’s ability to conduct electrons, or
its ability to allow electrons to move
through it
Substances with high electrical
conductivity will allow electrons to move
through them with the least amount of
resistance
Solution
A homogenous mixture of solute and
solvent
Solute
The substance that can be dissolved within
another substance
Solvent
The substance that can dissolve another
substance, present in larger amount
(commonly a liquid)
Electrolyte
Electrolytes are salts that dissolves in water and
produces ionized (charged) particles that are able
to conduct electricity.
