Science Unit 3: Chemistry, atoms, molecules; October 20, 2014

H3 PO3

7 atoms in each molecule

How many atoms are there in just one molecule of blood?

9,512

metallic bond

A bond formed by the attraction between positively charged metal ions and the electrons around them

cations have positive charges. Anions have negative charges. What force draws the two together?

electrostatic attraction

the atoms of a molecule come from two or more

elements

formula

short way of writing a compound

symbol

short way of writing an element

a chlorine atom has seven electrons and needs one additional electron to become

stable

Formula: HgO Named: mercuric oxide: Elements: Mercury (Hg) Oxygen (O) what is the number of atoms of each element and total number of atoms in one molecule

(hg) one atom; (O) one atom; total number of atoms: 2

HF

2 atoms in each molecule

what makes a molecule of oxygen gas?

2 oxygen atoms bonded together makes a molecule of oxygen gas

the total number of atoms in one molecule of starch is 6, 10, 16, 21

21

what is a formula?

A formula tells us which elements there are in a molecule. it also tells us how many atoms there are of each element. The formula for a compound is always the same. A change in the formula means that a new substance was formed.

Atom X has 10 electrons. Atom Y has eight electrons. which of them is more likely to bond with another atom?

Atom Y

what is the formula for starch?

C6 H10 O5. this stands for one molecule of starch.

balanced equation

Chemical equation with the same number of atoms of each element on both sides of the equation

law of conservation

Matter is not created nor destroyed in any chemical or physical change

what is the difference between atoms and molecules?

Molecules are made up of atoms. Each element on the periodic table of elements is made up of one single type of atom. molecules are formed when atoms bond. Different types of atoms can form together to make a molecule.

substance M is a blue, brittle solid. Substance N is a colorless, flammable gas. What can we predict about the compound created when M and N for a covalent bond?

There's no way to tell based on the information given

next, the coefficients are chosen to make the number of

______________ balance.

physical change

a change that effects one or more physical properties of a substance, many physical changes are easy to undo.

chemical change

a change that occurs when one or more substances are changed into entirely new substances with different properties, can not be reversed in any physical means

atoms that combine by sharing electrons form what

a covalent bond. An example is chlorine 2 sharing electrons; H2O are sharing

when two or more atoms bond this way they form a neutral particle called

a molecule

molecule

a neutral group of atoms held together by covalent bonds

coefficient

a number place in front of a chemical symbol or formula, used to balance a chemical equation

compound

a pure substance composed of two or more elements that are chemically combined

chemical equation

a shorthand description of a chemical reaction using chemical formulas and symbols

chemical formula

a shorthand notation for a compound or a diatomic element using chemical symbols and numbers

what is a symbol?

a written sign used instead of a word to represent something

which of the following atoms is most likely to bond with another atom?

an atom with 9 electrons

how many atoms of each of the following elements are in one molecule:

carbon: 3032; hydrogen: 4816; oxygen: 872; nitrogen: 780; sulfur: 8; iron: 4

a molecule is made up of?

atoms

opposite charges do what

attract each other

Coefficients are necessary to keep the numbers of atoms in

balance

You can only use coefficients to

balance the number of atoms on each side of the equation.

don not change the correctly written formula. If you change the formula of substance, the reaction is no longer

balanced

to show atoms are not lost or created during a reaction, the equation is

balanced

the number of molecules in a teaspoon of starch is twenty-one or billions

billions

C3032 H4816 O872 N780 S8 Fe4 a very special large molecule has thousands of atoms what is it called?

blood

a balanced chemical equation shows the same number of each kind of atom on

both sides of the arrow

write the number of atoms in CO2

carbon 1, oxygen 2

write the number of atoms in C55 H12 MgN4 O5

carbon 55, hydrogen12, magnisium 1, nitrogen4, oxygen 5

write the number of atoms in C6 H12 O6

carbon 6, hydrogen 12, oxygen 6

a group of symbols that represent a compound is a

chemical formula

the numbers that are placed on front of the symbols and formulas are called

coefficients

chlorine gas exists as particles made up of

compound of chlorine atoms.

CaF2

contains one kind of atom

element

contains one kind of atom

Atoms that combine by sharing electrons form a

covalent bond

This sharing of a pair of electrons is called a

covalent bond

symbols can be used for the states of mater:

cr or s = crystal or solid. l = liquid, g = gas, and aq = aqueous

what do hydrogen atoms and one oxygen atoms do? and HOw?

create water by bonding together

equations are balanced to show that atoms are not lost or

created during a reaction just rearranged.

A solid that has particles in a regular repeating pattern is called a

crystal

Elements such as chlorine form chlorine form molecules with two atoms are called

diatomic molecules

a compound is a substance formed when

elements combine chemically. This kind of change results in a compound with properties that my be very different from the elements that form it.

A way to show the changes that take place in a chemical reaction is to write a chemical

equation

the short hand method is

faster than writing than writing the word description of the reaction

there are more or fewer elements than compounds?

fewer

an atom has 15 total electrons. How many electrons does it have in its outer shell?

five

to balance an equation, first write the correct

formula for each reactant and ----------

atoms share, gain, or lose electrons in order to

have 8 electrons in their last energy level

when atoms combine chemically a bond is formed that

holds the atom together

write the number of atoms in H2O

hydrogen 2, oxygen 1

a charged particle is called an

ion

when a neutral atom loses or gains one or more electron, charged particle that results is called an

ion

Atom A has 7 electrons in its outer shell. Atom B has 1 electron in its outer shell. After bonding, both atoms now have 8 electrons in their outer shells. What kind of bond is

ionic

When ions bond together it is called

ionic bonding

bonding that occurs between ions is called

ionic bonding

Elements and what can form molecules?

ions

besides the formulas for the substances involved in the reaction, an arrow present to show what

is prduced

the relationship between the number of electrons in an atom's outer shell and the atom's tendency to bond is called the octet rule. What can you infer about the meaning of the

it refers to sets of eight

based on what you know about atomic structure, what can you infer about the word "nuclear?"

it relates to protons and neutrons

if an atom has no charge, which of the following must be true?

its number of protons is equal to its number of electrons

molecules are larger or smaller than atoms?

larger

by sharing, each chlorine atom has eight electrons in its outer energy what?

level

reactions between chemicals sometimes depend on the substances state of

matter. For example, some solid chemicals will not react when mixed together, but they will react when they are mixed in state

The ionic compound is different from this new particle, which is called a

molecule

When two or more atoms bond covalently, they form a neutral particle called a

molecule

when atoms bond covalently, there are no charges and the new particle is

neutral

can a single atom be considered a molecule?

no, it takes two or more atoms bonded to create a molecule

the neighboring chlorine atom is similar, thus they each share

one electron

write the number of atoms in O2

oxygen 2

molecules can be made up of two atoms of the same element; for example:

oxygen gas is made up only of oxygen atoms

In the ionic compound, instead of new molecules formed there is an orderly arrangement of

pairs

the atom that loses one or more electrons results in a

positive charge, while the atom that gains one or more electron results on a negative charge.

Formula: KCl; Name: potassium chloride; elements: potassium (K); chlorine (Cl) what is the number of atoms of each element and total number of atoms in one molecule

potasssium (K) has one atom; chlorine (Cl) has one atom; total number of atoms in one molecule is 2

Some substances are not soluble in water and when they are formed they will

precipitate out of a solution

substances to the right (or after) the arrow are the

product

any substances that are listed to the right of the arrow are called

products

elements in a compound always combine in the same

ratio. Ex. the ratio of carbon to oxygen in carbon monoxide (CO) is 1 to 1, and in carbon dioxide is 1 to 2

substances to the left (or before) the arrow are the

reactants

The smallest number in a formula that shows how many atoms of an element are present in a

subscript

when this is done, there will be the same number of each kind of

substance on both sides of the arrow

changing a formula will indicate a different

substance than the one indicated.

therefore it is necessary to note what state the substances are in by the use of

symbols

a chemical equation shows changes that take place during a chemical reaction using

symbols and formulas

One molecule of starch has two, six, ten atoms of hydrogen

ten

valence electron

the electrons in the outermost energy level of an atom. these electrons are involved in forming chemical bonds

ionic bond

the force of attraction between oppositely charged ions

covalent bond

the force of attraction between the nuclei of atoms and the electrons shared by the atoms

reactants

the starting materials in a chemical reaction

products

the substances form from a chemical reaction

numbers called coefficients are used in front of symbols and formulas (such as 2HCl) so

these numbers keep the number of atoms in balance.

starch is made up of one, two, three elements?

three

the number of different kinds of atoms in starch is

three

why does the author describe the atoms that make up water?

to give an example of a specific molecule

a single molecule has at least one or two atoms?

two

water molecules are made up of?

two hydrogen atoms and one oxygen atom

compound

two or more different kinds of atoms linked together

Explain why understanding bonding is important for understanding molecules.

understanding bonding is more important for understanding molecules because if atoms don't bond they can't make a molecule. (molecules can't exist without atoms)

when reading this reaction the arrow is read as

yields

the arrow in a chemical equation means

yields or produces