Science test (Chemistry) Flashcards
What is an isotope?
A form of the same atom that differ only in their number of neutrons
What is an electron?
A negatively charged particle within the atom
Atomic number
The number of protons an atom contains
What is the atomic mass?
The average mass of an atom
# of protons + # of neutrons
(sum of what is in the nucleus)
What are all of the diatomic molecules?
(Think: Have No Fear Of Ice Cold Beer)
Hydrogen
Nitrogen
Fluorine
Oxygen
Iodine
Chlorine
Bromine (Br)
How do you name a covalent bond from formula?
- Name first element, and add prefix if there is more than 1 atom of this element
- Name second element and add prefix and change the end to ide.
What is a chemical bond?
A chemical link between two or more atoms, holding the atoms together
Is the nucleus positively or negatively charged?
Positively charged
Periods. Horizontal or vertical?
Horizontal
Prefixes for 1 atoms, 2 atoms, 3 atoms, 4 atoms, 5 atoms:
1 = mono
2 = di
3 = tri
4 = tetra
5 = penta
What is an ion?
An atom lost or gained electrons.There are cations (positively charged), and anions (negatively charged)
What is a subatomic particle?
A particle that is smaller than an atom.These particles are found within an atom
What is an anion?
A negatively charged ion
Cation?
A positively charged ion
What is a molecule?
Two or more atoms chemically bonded together
Also known as the smallest discrete particle of a pure substance
What is a covalent bond?
A chemical bond that involves the sharing of electrons to form electron pairs between atoms.
Unlike an ionic bond, the electrons are not transferred from one atom to another. Instead, they are shared between the atoms.
Ionic bonds
A chemical bond between two oppositely charged ions; the metal becomes positively charged as it gives up electrons, and the non-metal becomes negatively charged as it gains electrons from the metal)
Chemical vs physical properties
Chemical properties can be observed or measured when a substance undergoes chemical change.
Physical properties do not need to undergo chemical change to be observed or measured.
Chemical vs physical change
Chemical change = chemical composition of substance changes or something new is created.
Physical change = substance change without anything new being created or without a change of chemical composition (Ex: a change in state of matter, or the substance being cut)
Qualitative vs quantitative physical properties
Quantitative physical properties = properties that can be measured or calculated
Qualitative physical properties = properties that are observed without measuring.
Ways to describe chemical properties (found during a chemical change):
Reactivity with other substances (with water, oxygen, and acid)
Combustibility (the ability of an element or compound to burn in the air)
Odour
Colour change
Precipitate(s)
Bubbles
Gas produced
Temperature change
Corrosion
Sublimation is when solid turns directly into a gas. How does this happen?
Sublimation occurs when the particles of the solid gain enough energy to lose the force of attraction between them.
Gain enough energy, lose force of attraction
Deposition is when
a gas turn directly into a solid
Pure substance vs mixture
Pure substance = made up of one type of particle and cannot be separated by any physical means
Mixture = a combination of different types of particles that retain their chemical identity
A pure substance can be an element or compound. What are they?
Element = one type of atom
Compound = two or more types of atoms chemically bonded
A mixture can be a homogeneous mixture or a heterogeneous mixture. What are they?
Homogeneous = appears uniform without (solution, where particles are all combined)
Heterogeneous (hetero is avg and on avg you can see components) = colloids (particles scattered evenly throughout) and suspensions (suspended particles will settle)
Create a graph showing the differences between metals and non metals and metalloids
GO!
Review the putting metals to work sheet (pg 66)
How does deposition occur?
For depostion to occur, thermal energy must be removed from a gas.
Selected property of chromium
Resists corrosion (good for chrome plating)
Selected property of copper and aluminum
Good conductor (good for electrical wiring)
Selected property of Nickel
Resists corrosion (good for coinage)
5 keys in particle theory:
- All matter is made up of particles
- All particle have space between them
- Particles are always moving
- Particles move faster and further apart when heated
- All particles are attracted to eachother
In covalent bonds, what do you draw in Lewis dot to show bond between 2 electrons?
1 line instead of the 2 dots
How do you know if the is molecule an ionic or covalent compound?
Ionic is made of metals and non-metals
Covalent is made up of non-metals only.
What does the staircase on the periodic table represent?
It shows where the metalloids are, and it is the transition between metals and non-metals
How do you name an ionic compund from formula?
- Write the name of the first element
- name second element and change the end to ‘ide’.
Atomic # = ?
= # of protons
Mass # = ?
= # of protons + neutrons
When atom gains electrons, negative charge is formed. When atom loses electrons what charge is formed?
Positive charge
To find number charge of an ion what formula do you use?
of protons -total # of electrons
Example of deposition
Frost. The water vapor in the air lies on a surface that has a temperature below freezing, turning the water vapor into frost.
An example of sublimation
Dry ice. When the solid/frozen carbon dioxide gets exposed to air it changes directly into a gas
Isotope vs Ion
An isotope is a form of an atom with a different number of neutrons than protons.
An ion is atom that has lost or gained electrons.
Why do atoms gain or lose electrons
To have full valence shells. Having full valence shells makes them more stable, which leads to them having more energy
Which
elements gives away valence electrons?
Metals
Which groups take away electrons?
15 (nitrogen family), 16 (oxygen family), and 17 (halogens).
The non-metals
Do happy campers ever become ions? Why?
Never. They have filled electron shells with no half-filled orbitals available for making covalent bonds
What are diatomic molecules?
Amolecule made up of only 2 of the same element (Ex: O2)
Phases are used in describing mixtures. What is a phase?
A distinctly uniform sample of matter is said to have one phase. (Ex: Coffee with cream and sugar)
Where are metals, metalloids, and non-metals located on the periodic table?
Metals: Left (majority)
Metalloids: along the staircase
Non-metals: right
What is a compound?
A substance made up of more than one type of element
Usual state of matter of metals:
Solids
Usual state of matter of non-metals:
Gases and powdery solids
Metal vs non-metals. Which has more lustre?
Metals
Metals vs non-metals. Which is more brittle?
Non-metals
Metals vs non-metals. Which are better conductors?
Metals
Metals vs non-metals. Which has a higher boiling and melting point?
Metals
Hydrogen is very explosive if not…
combined with other elements
What causes noble gases to glow?
An electrical current passing through them makes them glow
Metals include 2 groups we are focused on, which are:
Alkali metals
Alkaline Earth metals
Non-metals include 2 groups we are focused on, which include:
Halogens
Noble gases
Left to right of periodic table, atomic radius BLANK
Top to bottom, atomic radius BLANK
Blank 1: Decreases
Blank 2: Increases
Why does the atomic radius decrease from left to right of periodic table and increase from top to bottom?
When the atomic number gets higher, so does the number of protons. The more protons, the greater the amount of positive energy to attract the electrons (bring them in closer, decreasing the radius).
It increases down a group, because the number of energy levels (n) increases, so there is a greater distance between the nucleus and the valence shell
Positive and negative ions attract each other, creating…
Ionic compounds
With the Lewis Dot Diagram, what do you include
Element symbol and number of valence electrons in form of a dot
What is a subscript?
The number is written in the lower right corner to represent more than one atom of the element, chemically combined.
Subscript at the end of a bracket…
Multiplies with all of the subscripts in the bracket
Coefficient indicates the number of atoms of an element or molecule
3C vs C3
C C C vs C3(chemically combined)
How do we know atoms exist?
- chemical reactions we can observe their effects
- mathematic equations and indirect observations, we can calculate their various sizes
- the aid of new tech such as the scanning tunnelling microscope, we can see them.
What is an inert gas?
Another way to say ‘noble gas’
Characteristics of noble gases:
full valence shells
very stable and very low chemical reactivity
low melting and boiling points
Characteristics of alkali metals
very reactive
1 valence electron
high conductivity
Characteristics of alkaline earth metals
reactive but not as reactive as the alkali metals
2 valence electrons
good conductors
Characteristics of halogens
highly reactive
7 valence electrons
toxic
What is the difference between a molecular element, a molecular compound, and an ionic compound?
Molecular element: a molecule that is made up of atoms of the same element. Could also be called a diatomic molecule
Molecular compound: molecules comprised of atoms of different elements
Ionic compound: a compound formed when oppositely charged ions of different elements attract each other.
How do particles overcome attraction?
When energy is added in the form of heat, the particles aquire enough energy to overcome the force of attraction between them.
What is the difference between atomic number, mass number and the atomic mass?
Mass number: The sum of the number of protons and the number of neutrons in an atom.
Atomic number: The number of protons in an atom.
Atomic mass: The average mass of an atom, taking into account all its naturally occurring isotopes
