Concepts Flashcards
How do you know how many electrons are in a “neutral” atom?
The same number as protons.
Do atoms move?
Yes
How many electrons are in the first energy level?
2
How many electrons are in the second energy level?
8
What is the atomic number and where can you find it?
It tells the number of protons in an atom and is found above the element’s symbol on the periodic table.
What is the atomic mass of an atom and where can you find it?
It is the sum of the mass of the protons and neutrons and is found under the element’s symbol.
This book simplifies it a bit to counting protons and neutrons, but in real life, slightly different**
What is the difference between weight and mass?
Mass is teh same anywhere in the universe; weight is affected by gravity.
What is the difference between weight and mass?
Mass is the same anywhere in the universe; weight is affected by gravity.
All things are made of chemicals
Chemicals, which are made of molecules, which are made of atoms of elements
Chemistry is the science that studies chemicals
Chemicals
A ____ is a person who studies how chemicals interact
Chemist
A ________ is your best guess about the outcome of an experiment
Hypothesis
Chemists use two types of tests to tell different things apart—physical tests and chemical tests
Physical tests and chemical tests
Most chemicals are benign
TRUE
<p>Atoms are extremely small</p>
True
<p>Atoms are stationary</p>
False
<p>A Greek philosopher named \_\_\_\_\_\_\_\_\_\_\_ talked about the concept of atoms 2,400 years ago</p>
Democritus
<p>\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ affects how fast atoms move and the rate of diffusion</p>
Temperature
<p>A \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is needed to see atoms</p>
<p>The three parts of an atom are \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_</p>
protons, neutrons, and electrons
Electrons are found orbiting the nucleus in ___________
energy levels
<p>\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is/are found in the nucleus</p>
Protons and neutrons
________ and _________ are charged particles
Protons and electrons
<p>True or False: Protons, neutrons, and electrons are different depending on what atom they are in.</p>
False - a proton is a proton no matter what kind of atom it is in Same wiht neutrons and electrons.
Each type of ______ has a unique name
atom
<p>Atoms are mostly \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_</p>
empty space
What makes one type of atom different from another type of atom?
The number of protons that the atom has in its nucleus
The number of __________ a neutral atom has is the same as the number of protons in its nucleus
electrons
An _________ is a group of the same type of atoms
element
A maximum of ________ electrons go in the first energy level
two
A maximum of __________ electrons go in the second energy level
eight
When going from one type of atom to the next, one and only one ______ is added to nucleus
proton
True or False: Most atoms have more than one energy level
True
The __________ is a chart that has the names of all the elements on it
periodic table
True/False: Everything is made from elements in the periodic table
True
Elements are on the periodic table in abbreviated forms, called _________
symbols
____________ invented the periodic table
Dmitri Mendeleev
Why do some symbols have nothing in common with the name for the element?
Some symbols come from earlier names used for the element
The ___________ is found on your periodic table above the symbol for the element
atomic number
The atomic number equals the number of _______ in that type of atom
protons
The number of electrons in an atom’s elemental form equals the ________________
atomic number
If something is an __________, all parts of it will react the same in a chemical test
element
When going from one element to the next one on the periodic table, one ________ is added to the nucleus
proton
The ___________ of an element equals the number of protons + the number of neutrons
atomic mass
True or False: Mass is the same anywhere in the universe
True
True or False: Weight is the same anywhere in the universe
False. Weight is affected by gravity, so it isn’t the same anywhere in the universe.
Things that take up the same amount of space can have different ___________
masses
If the number of the same type of atoms stays constant, the liquid state weighs the SAME or MORE or LESS as the solid state
same
What does a.m.u. stand for?
atomic mass unit
________ is the unit used to measure the atomic mass of an atom
a.m.u. or atomic mass unit
The rows of the periodic table are called ________
periods
There are ______ periods on the periodic table
seven
True or false: The periodic table is read from left to right and down, like a book
True
The _______ an element is in equals the number of energy levels it has
period
The columns of the periodic table are called _______
groups
Elements in the same _______ on the periodic table share traits with each other
group
There are ______ groups on the periodic table
18
Elements in the same group have the same number of ____________________
electrons in their outer energy level
The top three _________ on the periodic table have 18 commonly occurring elements
rows (periods)
_________ of the 118 elements are naturally occurring, the rest are man-made
92
One and only one _____________ is added to the nucleus of an element when going from one element to the next on the periodic table
proton
The number of _______ in an element’s nucleus equals its atomic number
protons
The__________ of an element equals the atomic number plus the number of neutrons
atomic mass (By the way, this is conceptual and simplified for kids, not exactly true. It's the total of the mass of the protons and neutrons, which is not exactly 1.)
The total number of ________ for elements on the periodic table equals the number of ______ for that element
electrons, protons
All elements in the same group have the same number of _____________________________
electrons in their outer energy level
The number of ________ does not increase consistently from one atom to the next, but does increase overall
neutrons
Introduction to the elements hydrogen, lithium, and sodium
Answer
Things are (more or less) buoyant in NaCl + water than in water alone
more
Introduction to the elements hydrogen, lithium, and sodium
Answer
A solution = ______ + ________
A solution = solute + solvent
________ is the universal solvent
Water
Introduction to the elements boron and aluminum
Answer
Introduction to the elements carbon and silicon
Answer
________ browns when heated
Carbon
Sugar is made from _____________
carbon, hydrogen, and oxygen
Introduction to the elements nitrogen and phosphorus
Answer
Introduction to the elements oxygen and sulfur
Answer
When hydrogen peroxide bubbles it is turning into ______________
water and O2
Hydrogen peroxide bubbles on cuts because of _________ in your blood, not germs in the cut
catalase
Introduction to the elements fluorine and chlorine
Answer
__________ bonds to calcium in teeth making teeth stronger
Fluorine
Introduction to the elements helium, neon, and argon
Answer
Gas SHRINKS or GETS BIGGER when it is cold
shrinks (has a smaller volume)
Atoms bond (link) together and make ________
molecules
The bonds form when atoms share _________________
electrons from their outer energy levels
A _________ is a group of all the same type of molecules
compound
A _________ is a group of different types of molecules
mixture
____________ tell the amount and type of atoms present in a molecule
Molecular formulas
To write a _______________, write the symbol for the element and the number of _______ present
molecular formula, atoms
___________ in plants is a result of the interaction between water molecules and the cellulose molecules in the plant
Capillary action
A special method for drawing molecules called that uses dots
Electron Dot Structures
When drawing molecules with Electron Dot Structures, place the atoms so they are sharing ______ on the side where there is a single electron
electrons
Electron Dot Structures pair _______ from different atoms using only _____________________
electrons,
electrons in the atoms’ outer energy levels
The rate of ___________ can be affected by how “sticky” water finds molecules it encounters in something like a plant
capillary action
Protons + neutrons + electrons make ________
atoms
Atoms group together to make ________
molecules
Molecules group together to make _______
matter
Sometimes when two different types of molecules get together, they switch atoms around and make different molecules. This is called a __________
chemical reaction
When chemical reactions happen, _______ cannot be created or destroyed
atoms
__________ wrote the Atomic Theory of Matter in 1766
John Dalton
________ is anything that takes up space and has mass (weight).
Matter
Matter comes in three states—name them.
solid, liquid, and gas
The three states of matter are differentiated by the physical properties of ___________________
definite shape and volume
True or False: Water is found in all three states—ice, liquid water, and steam—over the normal temperature range
True
The special name for the point where matter goes from solid to a liquid _____________
melting point
The special name for the point where matter goes from liquid to a solid
Freezing point
The special name for the point where matter goes from gas to a liquid
Condensation point
The special name for the point where matter goes from liquid to a gas
Boiling point
The temperature of the freezing point = the temperature of the _______________
melting point
The temperature of the boiling point = the temperature of the _____________
condensation point
Boiling point of water = condensation point = what temperature in Fahrenheit and Celsius?
212˚F (100˚C)
The melting point of water = freezing point = what temperature in Fahrenheit and Celsius?
32˚F (0˚C)
True or False: Some matter does not fall completely into one of the three defined states
True
The molecules in a ________ are close together
solid
The molecules in a _______ do not move much, they vibrate slightly and have a fixed position relative to each other
solid
True or false: Solids are less dense than gases.
False. Solids are MORE dense than gases.
The amount of stuff in a given space
Density
_______ have a definite shape and a definite volume
Solids
Solids are more dense than liquids, with the important exception of _________
water
_______ is affected by the amount and type of molecules or elements present
Density (there are probably other things that could fit here too, but at the moment this section is about density)
Molecules stick together by sharing __________
electrons
Molecules in _____ are close together and don’t move much
solids
Molecules in liquids are farther apart and move more than in ________
solids
Molecules in ______ are not very close together—they move a lot
gases
The molecules in a ______ are close together but not as close as in a solid
liquid
The molecules in a liquid move around but not as much as in a _________
gas
_________ have a definite volume, but not a definite shape
Liquids
True or False: Different types of liquids can have different densities
True
True or False: Water is essential to life, as we know it
True
_______ bonds hold water molecules together
Hydrogen
Because ice is MORE or LESS dense than liquid water, the same number of molecules in ice has a GREATER or SMALLER volume than those molecules in liquid water
less dense / greater volume
Water can be separated into hydrogen and oxygen gases through a process called ______________
electrolysis
The molecules in a _____ have a lot of space between them
gas
The molecules in a ________ are fluid, move very fast, and mix freely
gas
______ do not have a definite volume or a definite shape
Gases
Gases are MORE or LESS dense than solids and liquids
less
Because gases are less dense than liquids, they will __________
float to the top and out of a liquid
True/False: Oxygen is essential to life
True
True or False: Air doesn’t take up space
False. Air takes up space!
Air is 78% nitrogen and 21% oxygen. ________ is cycled between people, animals, and plants
Oxygen
True or False: Air is important for regulating the temperature on earth
True
True or false: In a chemical reaction, the molecules at the beginning are NOT the same as those at the end
True
True or false: In a chemical reaction, the atoms at the beginning are NOT the same as those at the end
False: The same atoms are there, but they are bonded differently
When there is a __________ change, the molecules present do not change
physical
In a chemical reaction, the starting molecules are called _____________
reactants
In a chemical reaction, the ending molecules are called ______________
products
What are three evidences of chemical change?
temperature change,
the formation of bubbles, or
a solid forming
Chemical reactions are written as equations
Answer
___________ reactions release heat
Exothermic
___________ reactions absorb heat
Endothermic
Acids taste __________
sour
Bases taste __________
bitter and feel slippery
________ tell if a solution is an acid, a base, or neutral
Indicators
In _______, the hydrogen atom comes off in a solution and leaves an electron
acids
In acids, the hydrogen atom comes off in a solution and leaves an electron. This is called a ___________.
dissociation reaction
In _______, the oxygen and hydrogen atoms come off in solution and take electrons
bases
In bases, the oxygen and hydrogen atoms come off in solution and take electrons. This is called a __________
dissociation reaction
acid + base = water + salt = ____________
an acid-base reaction
H without its electron (from an acid) and OH with an electron (from a base) makes _______
H2O
If an acid and a base solution are mixed, and the resulting solution is neutral, it is called a __________ reaction
neutralization
The____________ is used to measure the strength of an acid or a base
pH scale
The pH scale measures from ___ to ____
0 to 14
What number is neutral neutral on the pH scale?
7
A value less than 7 on the pH scale is a/an _________
acid
A value greater than 7 on the pH scale is a/an _________
base
In precipitation reactions, different ______ are mixed together and one of the products formed is a _____
LIQUIDS are mixed together / one of the products formed is a SOLID
______________________ reactions are the type of chemical reactions used to make bones, teeth, shells, and coral reefs
Precipitation
Combustion reactions must have ________________ as one of its reactants
oxygen gas
Are combustion reactions are exothermic or endothermic?
exothermic
What happens if oxygen gas is taken away from a fire?
The fire goes out and the reaction stops
Air is ____% nitrogen and ____% oxygen.
Air is 78% nitrogen and 21% oxygen.
