Chemistry Flashcards
What are ions?
Ions are atoms that have gained or lost valence electrons
What are chemical compounds?
2 or more atoms joined together by a chemical bond
What are the 2 types of chemical compounds?
Ionic and Molecular
Most ________ want to lose their valence electrons
metals
What is one reason that an element would be stable?
Because they have a full valence oribital
What is the scientific method parts in order?
Purpose, Hypothesis, Variables, Materials, Procedure, Results, Conclusion
What are the two types of observations in the scientific method?
Qualitative and Quantitative
What part of the scientific method do you write where the results mean?
The conclusion or abstract
Are zeros considered significant figures if they are at the end?
Only if they have a decimal at the end or before the zero
Are leading zeros considered signifcant figures?
Leading zeros are never significant
What WHMIS symbol can cause birth defects in children and cancer?
Health Hazards
What WHMIS symbol can damage the ozone layer?
Harmful materials
What WHMIS symbol can cause eye and skin irratation? What about affect the water ways?
Harmful Materials, Environmental Hazards
What does WHMIS stand for?
What does HHPS stand for?
Workplace Hazardous Materials Information System.
Hazardous Household Product Symbols.
What are the three formulas for density?
M = V x D, V = M / D, D = M / V
What does GRASP stand for?
Given, Required, Analysis, Solution, Paraphrase
What are the five signs of a chemical change?
- Colour change
- New heat or light
- Gas is given off
- Prescipitate
- Hard to reverse
Why is a chemical change different than a physical change?
Physical change: The substance remains the same substance
Chemical change: The original substance is changed into one or more new substances
What are the three parts of a good hypothesis?
“If…. Then… Because”
Are these chemical or physical changes? Burning, Boiling, Rusting, Dissolving, Breaking, Melting, State change, Condensing, Reacting.
C, P, C, P, P, P, P, P, C.
What are the units for mass, density, and volume?
Density = g per cm cubed
Mass = g
Volume = cm cubed
What is the gas test for oxygen?
Carbon dioxide?
Hydrogen?
Glowing splint - reliting splint
Limewater - turned cloudy (straw)
Burning splint - small explosion
What are the diatomic elements?
Hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine
What are the three main classes of elements?
Metals, non metals, and metalloids
What element doesn’t belong to any of the classes?
Hydrogen
What class of elements have properities in between the two other classes?
Metalliods
What class of elements are semi conductors and have weak magnetic properities?
Metalloids
Hydrogen has some physical properities similar to ______ _________
non metals
What state (s) are non metals at room temperature?
What about metalloids and metals?
non metals - solids or gases
metalloids - solids
metals - solids (general)
hydrogen - gas
What class of elements is shiny and not shiny?
shiny - metals
not shiny - non metals
Are non metals magnetic or conductors?
No
What class of elements are brittle?
What about malleable and ductile?
Non metals
Metals
Do metals usually react with acids?
Yes
What is a chemical symbol?
An element name abbreviated
What is a chemical formula?
They are used for compounds and have a combonation of chemical symbols.
What are subscripts?
The number of atoms of that element are in a molecule of that compound
How many electrons can each orbital hold?
1st - 2
2nd - 8
3rd - 8
What subatomic particles live in the nucleus?
Protons and neutrons
Can electrons exist between orbitals?
No
What are valence electrons?
The electrons on the outer orbital of an atom
What are used to represent valence electrons on a lewis diagram?
x’s
The number of protons _________ ____ _________.
Defines the element
What charge do atoms have?
0
Neutrons act as the _____ that allows the nucleus to stick together.
glue
What are isotopes?
A term for the fact that atoms of the same element can have different numbers of neutrons
Are protons attract or repel each other?
repel
What are the two physical properities that the number of neutrons affect?
Mass and Density
Name the five scientists that contributed to the history of the atom:
- John Dalton
- J.J Thomson
- Ernest Rutherford
- Niels Bohr
- Erwin Schrodinger
What are the models of the atom for each of the following scientists?
- John Dalton - Solid Sphere Model
- J.J Thomson - Plum Pudding / Raisin Bun Model
- Ernest Rutherford - Nuclear Model
- Niels Bohr - Planetary Model
- Erwin Schrodinger - Quantum Model
What are John Daltons theories about the atom?
That atoms are indivisible, those of the same element are identical, and that compounds are a combonations of different types of atoms.
What did J.J Thomson discover?
He discovered electrons in the atom in 1897. He created the plum pudding model that shows electrons scattered in a cloud of positive charge.
Which scientist did a gold foil experiment? What did this experiment show?
Ernest Rutherford. The experiment showed that the atom must be mostly empty space. Some positively charged atoms were repelled by the gold foil meaning that the nucleus had a positive charge.
What did Niels Bohr propose?
That electrons exist in stable orbitals
What is the widely accepted model of the atom? Who proposed this?
The Quantum model. Erwin Schrodinger stated that electrons don’t move in set paths around the nucleus but in waves.
What are the types of elements involved in Ionic and Molecular compounds?
Ionic : Metal and non metal
Molecular : Non metals and non metals (2 or more)
Which compound is soluble in water?
Ionic Compounds
What happens to electrons in compounds?
IC: electrons transferred metal to non metal
MC: electrons shared between the atoms
What are the structures of IC and MC compounds?
IC: crystals / lattice
MC: powder
What compounds conduct electricity when dissolved in water?
IC: yes
MC: no
What is a compound?
A substance composed of two or more elements that act together as one
Who proposed the existance of the nucleus in atoms?
Ernest Rutherford
Ionic compounds usually have _______ / ________ structures
lattice / crystal
Molecular compounds usually have ________ structures
powder
Ionic compounds have _____ melting and boiling points. Molecular compounds have _____.
high , low
IC have a ______ ratio, MC __ ____
fixed , do not
Electrons will naturally fill the ______ ________ ______ before the higher ones.
lower energy states
orbitals ______ to the nucleus are lower energy states
closer
What is the second sign of a chemical change?
- heat or light is given off
Electrons will fall back to their ________ ______ (original orbital) after being in an excited state.
Ground state
List four properties of Ionic compounds:
- bonding of a metal with a non metal
- conduct electricity with dissolved in water
- soluble
- crystal structure
List four properties of Molecular compounds:
- bonding of 2 or more non metals
- insoluble
- powder structure
- low boiling and melting point
Dalton’s atomic theory, atoms are considered to be _____ ___________ ________
Tiny indivisible spheres
What couldn’t Dalton’s model explain?
Electricity