Chemistry Flashcards
What are the parts of an atom?
Atoms consist of structures within the nucleus containing protons and neutrons.
What is a proton?
A particle with a single positive charge.
What is a neutron?
A particle with no electric charge.
Where are electrons found?
Electrons orbit around the nucleus and shells.
What is an electron?
A particle with a negative charge.
In atoms, the number of protons and electrons are ____.
Equal
What determines the type of an element?
They are determined by the number of protons within the nucleus.
What are isotopes?
Atoms of the same element that have a different number of neutrons. They have the same atomic number and position in the periodic table but differ in the number of neutrons.
What does the atomic mass of an atom represent?
The total number of protons and neutrons.
How do you calculate the atomic mass of an atom?
Add the number of protons and number of neutrons together.
What is the formula to find the number of neutrons?
Neutrons = mass number - atomic number
What does the atomic number of an atom represent?
The number of protons in an atom.
Atoms can be ____ charged, ____ charged, or ____.
Positively, negatively, neutral.
What determines if an atom is positively charged, negatively charged, or neutral?
The number of electrons compared to the number of protons in an atom.
An atom will be negatively charged if there are more ____ than ____.
Electrons, protons.
An atom will be positively charged if there are more ____ than ____.
Protons, electrons.
An atom will be neutral if the number of protons and electrons are ____.
Equal
What is an ion?
An atom that has gained or lost electrons, and as a result, have a charge that’s either positive or negative.
What are the 2 types of ions?
Cations and anions.
What is a cation?
An atom that lost one or more electrons and has a resulting positive charge.
What is an anion?
An atom that has gained one or more electrons and has a resulting negative charge.
When an atom gains electrons, where does it usually take place?
Within its most outer shell. Only electrons in the outermost shell participate in chemical reactions.
How are the elements organized in the periodic table?
They are organized by increasing atomic numbers. The columns go from left to right in order of increasing atomic number. The rows go from top to bottom in order of increasing atomic number.
What are the columns of the periodic table called?
Groups
What do the groups (columns) on the periodic table represent?
The number of valence electrons found within the atom.
Elements in the same group on the periodic table are elements with similar ____.
Chemical properties
What are the rows of the periodic table called?
Periods
What do the periods (rows) on the periodic table represent?
The number of electron shells.
What do all elements in the same period on the periodic table have in common?
They have the same number of electron shells.
What are the first two rows of the periodic table considered as?
The active metals
What is the middle of the periodic table considered as?
The reactive metals.
What is the far-right column of the periodic table considered as?
The inactive gases.
What are the elements that don’t fit perfectly in the periodic table called?
Transition elements or metalloids.
How many valence electrons do transition elements/metalloids have?
1 or 2
What is the octet rule?
Atoms are most stable when their valence shells are filled with 8 electrons.
The octet rule primarily influences an atom’s ____.
Electron configuration
What are orbitals?
Areas where electrons are likely to be found.
What are the 4 types of orbitals (shells)?
s orbital, p orbital, d orbital, and f orbital.
What is the s orbital (shell)?
A spherical area surrounding the nucleus.
What is the max number of electrons for the s orbital?
2
What is the p orbital?
A dumbbell-shaped area surrounding the nucleus.
What is the max number of electrons for the p orbital?
6
What is the d orbital?
A clover-shaped area surrounding the nucleus.
What is the max number of electrons for the d orbital?
10
What is the f orbital?
An irregularly-shaped area surrounding the nucleus.
What is the max number of electrons for the f orbital?
14
The number of orbitals an element has is the same as the ____ it has on the periodic table.
Period number
Where are valence electrons found?
In the outermost shell of an atom, ready to participate in chemical reactions.
Regarding valence electrons, elements are most stable when ____.
They have a full valence shell.
How are ionic bonds formed?
When atoms trade electrons in order to achieve stability.
How are covalent bonds formed?
When atoms share electrons in order to achieve stability.
What 4 major elements mostly form covalent bonds?
Carbon, oxygen, hydrogen, and nitrogen.
What is matter?
Anything that has mass and occupies space.
Matter can be ____, ____, and ____.
Solid, liquid, gas.
What are physical properties?
Different properties of a substance that can change its state (gas, liquid, solid) without changing the identity of the substance.
What is mass? What is it measured in?
The amount of matter in an object. It is a measure of inertia of an object and is measured in grams (g) or kilograms (kg).
What is volume? What is it measured in?
The amount of space an object occupies and is measured in liters (L) or milliliters (mL).
What is density? What is it measured in?
It is a measurement of how much matter is packed into a given space and is measured in grams per liter (g/L).
How do you calculate density of an object?
Density = mass/volume
The density of a substance can be affected by its ____.
Temperature
When a substance matter changes, the ____ also change.
Physical properties
What are the states of matter?
Solids, liquids, gases, and plasma.
What are solids (regarding states of matter)?
They have a definite shape and volume. They are not compressible. The molecules are packed together in a tight pattern and are anchored at a specific location.
What are liquids (regarding states of matter)?
They have a definite volume but take the shape of their container. They are not compressible. The molecules are packed close together but are not fixed.
What are gases (regarding states of matter)?
They have neither a definite shape nor volume, but they are compressible. The molecules are far apart from each other.
What is plasma (regarding states of matter)?
It’s a state of matter that is often found in the stars. It is a gas that is ionized, meaning that electrons have been stripped from the atoms.
What 2 conditions is the phase of a substance dependent on?
Temperature and pressure
What is temperature (regarding states of matter)?
A measure of the average kinetic energy of the molecules in a substance. The higher the temperature, the more energy the molecules have (move particles of matter apart) and the more space they take up.
What is pressure (regarding states of matter)?
A measure of the force exerted on an object by the surrounding atmosphere. The higher the pressure, the more the molecules are forced together.
What is condensation?
The process where a gas loses heat and turns into a liquid.
When does condensation occur?
This happens when the molecules of the gas slow down and become closer together.
What is evaporation?
The process of a liquid changing to a gas, usually when the liquid is heated.
When does evaporation occur?
This happens when the molecules of the liquid gain enough energy to break away from the surface of the liquid.
What is sublimation?
The process where a solid changes directly into a gas without first becoming a liquid.
When does sublimation occur?
This happens when the molecules of the solid gain enough energy to break away from the surface of the solid.
What is deposition?
The process where a gas changes directly into a solid without first becoming a liquid.
When does deposition occur?
This happens when the molecules of gas slow down and become closer together.
What is melting?
When a solid gains heat and changes into a liquid.
When does melting occur?
This happens when the molecules of the solid gain enough energy to break away from each other.
What is freezing?
The process where a liquid loses heat and turns into a solid.
When does freezing occur?
This happens when the molecules of the liquid lose enough energy to stay together.
Elements are most stable when ____.
They have a full valence shell.
Valence electrons located in the outermost shell of an atom readily participate in ____.
Chemical reactions
Atoms can ____ or ____ valence electrons in order to achieve a full outer energy level. When this happens, the atom will form a ____ with another atom.
Gain, lose, chemical bond.
Ionic bonds are normally formed between a ____ and ____.
Metal, nonmetal.
Covalent bonds are normally formed between two ____.
Nonmetals
Oxygen and hydrogen form ____ bonds.
Covalent
What is a chemical reaction?
One or more substances, known as reactants, that are transformed into different substances called products.
What are the reactants in chemical reactions?
The substances that are involved in the reaction.
What are the products in chemical reactions?
The new substances that are formed by the reaction.
What is the formula that represents a chemical reaction?
Reactants –> Products
A chemical reaction must be ____. What does this mean?
Balanced. This means that there must be the same number of atoms of each element on both sides of the arrow.
What is a mole (in chemical reactions)?
The unit that is used to measure the amount of a substance.
What can a mole (in chemical reactions) be measured by?
The number of atoms, molecules, or mass of a substance.
What is the equation for a mole (in a chemical reaction)? What is it also called?
6.022 x 10^23. Avogadro’s number.
What are 5 types of common chemical reactions?
Combination/synthesis, decomposition, displacement, double displacement, and combustion.
What is the chemical reaction combination/synthesis?
2 or more substances combine to form a single product.
A + B → AB
What is the chemical reaction decomposition?
A single substance breaks down into 2 or more simpler substances.
AB → A + B
What is the chemical reaction displacement?
1 element in a compound is replaced by another element.
A + BC → AC + B
What is the chemical reaction double displacement?
Elements in 2 different compounds swap places with each other to form 2 new compounds.
AB + CD → AD + BC
What is the chemical reaction combustion?
A substance (usually hydrocarbon) reacts with oxygen to produce heat, light, and typically produces carbon dioxide and water.
CxHy + O2 → CO2 + H2O + FIRE
What is the hallmark sign of a combustion chemical reaction?
The second reactant is oxygen, and the products are carbon dioxide and water.
What makes a chemical reaction balanced?
The reactants are the same exact number as your products. ** balance oxygen and hydrogen last when balancing chemical reactions **
What is collision theory?
For particles to react, they have to collide with each other with sufficient energy.
What factors influence reaction rates?
Catalysts, temperature, concentration/pressure, and surface area.
What are catalysts? What are they known as?
They speed up reactions. Enzymes
What are endothermic reactions?
Reactions that absorb heat.
What chemical reactions are examples of endothermic reactions?
Cooking an egg, photosynthesis, and liquid evaporation.
What are exothermic reactions?
Reactions that release heat.
What chemical reactions are examples of exothermic reactions?
Combustion reactions, oxidation, and neutralization.
What is equilibrium?
The rate of the forward reaction is equal to the rate of the reverse reaction.
What are the 2 types of equilibrium?
Dynamic equilibrium and static equilibrium.
What is dynamic equilibrium?
The forward and reverse reactions are occurring at the same time.
What is static equilibrium?
Concentrations of the reactants and products are not changing.
The position of equilibrium can be shifted by ____?
Adding or removing reactants and products.
What is activation energy?
The minimum amount of energy that is needed for a chemical reaction to occur.
What is cohesion?
The process of a similar molecule surrounding and binding to another molecule.
What is adhesion?
The process of dissimilar molecules binding to another molecule.
What is a solvent?
A substance that dissolves in another substance.
What is the most universal solvent?
Water
What is a solute?
A substance that dissolves in a solvent.
What is the most common solute?
Sugar
What is solubility?
The ability of a solute to dissolve in a solvent.
What is solubility limit?
The amount of solute that can dissolve in a given amount of solvent.
Hydrophilic means ____.
Water-loving
Hydrophobic means ____.
Water-fearing
What is the concentration of a solution?
The amount of solute in a given volume or space.
What is dilution?
The process of adding solvent to a solution to decrease the concentration of the solution.
What is molarity? What is it expressed as?
A unit
What is the solubility limit?
The amount of solute that can dissolve in a given amount of solvent.
Hydrophilic means ____.
Water-loving.
Hydrophobic means ____.
Water-fearing.
What is molarity? What is it expressed as?
A unit of measurement that describes the concentration of a solute in a solution. It’s expressed as moles of solute per liter of solution (mol/L).
What is osmosis?
The process of water molecules moving from an area of high water concentration to an area of low water concentration through a semi-permeable membrane.
Osmosis refers to the movement of ____.
Water.
Diffusion refers to the movement of ____.
Particles (not water).
What is diffusion?
The process of molecules moving from an area of high concentration to an area of low concentration.
What factors affect diffusion?
Distance, temperature, solvent characteristics, and traveling characteristics.
The greater the distance, the ____ the diffusion rate.
Slower.
Higher temperature causes an ____ in diffusion rate.
Increases.
Increased density can ____ molecules down and ____ diffusion.
Slow, decrease.
The greater the mass, the ____ the diffusion rate.
Lower.
What is facilitated diffusion?
Movement of larger particles.
Osmosis and diffusion are both ____ processes.
Passive transport.
What is passive transport?
Processes that do not require energy, they only require that the molecules be in motion.
What is active transport?
The process of molecules moving from an area of low concentration to an area of high concentration. This process requires energy.
What is a hypertonic solution?
Higher solute concentration.
What is an isotonic solution?
Contains the same concentration of water and solutes.
What is a hypotonic solution?
Lower solute concentration.
What is an acid?
A molecule that increases the concentration of hydrogen ions in a solution.
What is a base?
A molecule that decreases the concentration of hydrogen ions in a solution.
The pH scale ranges from ____ to ____.
0 to 14.
A pH lower than 7 is considered ____. It is considered a(n) ____.
Acidic, acid.
A pH higher than 7 is considered ____. It is considered a(n) ____.
Alkaline, base.
A pH of 7 is considered ____.
Neutral.
Blue litmus paper turns ____ under acidic conditions.
Red.
Blue litmus paper turns ____ under alkaline conditions.
Blue.
What type of ions does alkalis produce in water?
Hydroxide ions (OH-).
What is formed when an acid reacts with a base?
Salt and water.
What is the reaction between an acid and a base called?
Neutralization.
What is a buffer?
A solution that can resist changes in pH.
What do buffers help with?
They help with maintaining the pH of a solution within a certain range.
What is a neutralization reaction?
A chemical reaction between an acid and a base.
