Unit 2 Flashcards
Define element
An element contains 1 type of atom
Define mixture
2 or more different types of atoms not chemically bound
Define compound
2 or more different types of atoms chemically bound
Define isotopes
different atoms of the same element that have the same number of protons and electrons but a different numbers of neutrons
Formula for isotopes mass
[(atomic mass x percentage its found) + (atomic mass x percentage its found)] / 100
Define metallic bonds
electrostatic attraction between negative delocalized electrons and positive metal nuclei
Define ionic bonds
electrostatic attraction between positive metal ions and negative non metal ions
Define covalent bonds
electrons shared between non-metal atoms
Define ion
Charged particle
Are melting and boiling points for ionic and metallic compounds high or low? Why?
High because there are many bonds between the positively charged ions and negatively charged ions and the electrostatic forces are strong
Are melting and boiling points for covalent molecules high or low? Why?
Low because the intermolecular forces are weak
Are intermolecular forces strong or weak? What is the effect of this?
Weak. it affects substances by making it easy to change states and making it have a low melting and boiling point
what are the structures called when the bonds are in 3 directions?
giant metallic lattices and giant ionic lattices
define simple molecules
singular molecules (except sand and carbon bonded molecules)
What is the state of fluorine at room temperature? what colour is it?
gas. yellow
What is the state of chlorine at room temperature? what colour is it?
gas. yellow-green
What is the state of bromine at room temperature? what colour is it?
liquid. brown
What is the state of iodine at room temperature? what colour is it?
solid. brown-black
state 4 facts about diamond
-Made of carbon
-doesn’t conduct electricity because it doesn’t have delocalized electrons
-Not soluble
-4 covalent carbon bonds
state 4 facts about graphite
-made of carbon
-does conduct electricity because it has delocalized electrons so charge can flow
-Not soluble
-3 covalent carbon bonds
-it is soft and slippery
state 3 facts about silicon dioxide
-SiO2
-doesn’t conduct electricity because it doesn’t have delocalized electrons
-Not soluble
Can ionic compounds conduct electricity? why?
Only when molten or aqueous because ions are only free to move when molten or an aqueous solution
Can covalent molecules conduct electricity? why?
No because there are no free to move ions (except graphite)
Can metallic molecules conduct electricity? Are the malleable and ductile? why?
Yes because the layers can slide over one another and can move
Can ionic compounds dissolve in water?
Most do, Yes
Can covalent molecules dissolve in water?
mostly no, No
Can metals dissolve in water? why?
No because the bonds are strong
what is the relationship between group 1 metal and water?
group 1 metals are reactive with water but are not soluble in water
define independent variable and give 1 example
usually on x axis, the thing that changes (concentration of salt in osmosis)
define dependent variable and give 1 example
usually on y axis, the thing that we measure (the length of potato in osmosis)
what should the sentence structure be for describing trends on a graph?
As x-axis goes up, what happens to y-axis?
as the atomic radius gets bigger, does it get easier or harder to remove electrons? why?
Easier. because the electrons are further away from the nucleus so there is less attraction and there are more shells which is more shielding so theres lower attraction
as the atomic radius gets bigger is it more reactive or less reactive?
more reactive
as the atomic radius gets bigger, does it get harder or easier to attract electrons? why?
harder because the electrostatic attraction is weaker (its further apart and more shielding)
define atom
smallest unit of matter that can’t be broken down more
why do isotopes have the same chemical properties?
because they have the same electronic configuration
define ductile and is it a physical or chemical property?
can be pulled into a wire, physical property
define malleable and is it a physical or chemical property?
can be hammered into a shape, physical property
define high conductivity
can conduct thermal energy and electricity
why can substances transfer energy? (electrons)
because electrons are free to move
what are word equations? (use example to explain)
2.8.1 + 2.8.7 = 2.8+ + 2.8.8-
what are symbol equations? (use example to explain)
Na + Cl2 = NaCl
what does the atomic number tell us?
how many protons there are
what does the atomic mass tell us?
mass of / number of protons + neutrons
formula for number of neutrons
atomic mass - atomic number
difference between element and ion
an element is a not charged particle and an ion is a charged particle
define occupied electron shells
shells with electrons in the shells
what is the pattern in a metallic bond?
electrons are free to move and delocalized and protons have a regular pattern
what is the physical properties of mass and density of isotopes?
have different mass and density because number of neutrons is different
does an element and atom have a charge?
no
does an ion have a charge?
yes
formula for atomic mass
number of protons + number of neutrons
define radioactive
nucleus is unstable
as the atomic radius gets smaller, what happens to the energy level?
decreases (get lower)
what are 3 ways to say ‘how electrons are arranged in shells’
-electron arrangement
-electron distribution
-electronic configuration
define impurities
unwanted substance mixed with wanted usbstsance
define pure substance
only particles of own substance/no particles of other substances mixed in
define brittle
breaks easily when struck
define sonorous
makes a ringing noise when struck
are metals brittle? are metals sonorous? are metals good conductors? are metals ductile? are metals malleable?
no, no, yes, yes, yes, yes
define diatomic
elements made up of molecules containing 2 atoms
do molecular substances have low or high melting and boiling points? why?
low because forces between molecules (intermolecular forces) in the lattice are weak
what are halogens?
most reactive non metals (group 7)
what are noble gases?
most unreactive non metals (group 8)
what groups have the most reactive metals?
1 and 2
what are magnetic metals?
Fe, Co, Ni
define valency electrons
The electrons in an atom’s outer shell
What happens to a radioactive nucleus
Atom breaks down naturally (decays) giving our radiation in the form of rays and particles and a large amount of energy
What are 3 uses of radioisotopes?
-To check for leaks
-to treat cancer
-to kill germs and bacteria
What type of electron decides how an element reacts?
Valency electrons
Why do atoms form bonds?
To have a stable outer shell
Define ionic compound
Substance made of ions
Define compound ions
Ions formed from a groop of bonded atoms
Define molecules
A group of atoms held together by covalent bonds
Define covalent compounds
Atoms of different elements sharing electrons
What shape are molecules?
Tetrahedral
3 properties of ionic compounds
-good conductor if aqueous or molten (bad if solid)
-soluble in water (generally)
-high melting and boiling point
