General Chem Review for Organic Chem Chapter 1

Element:

the simplest type of substance with unique physical and chemical properties

An element consists of only one type of?

atom

Elements can be diatomic:

H2, N2, O2, F2, Cl2, Br2, I2

Molecule:

a structure that consists of two or more atoms that are chemically bonded together and thus behaves as an independent unit

Al=

an element, but not a molecule

H2=

an element, and it is a molecule

Compound:

a substance composed of two or more different elements which are chemically combined. It may army not involve a sharing of electrons between the atoms

O2=

molecule of an element

H2O=

molecule of a compound

NaCl=

compound but not a molecule; NaCl exists as Na+ and Cl- ions that are attracted to each other (ionic bonding) but they are not bonded together by sharing of electrons (covalent bonding)

ion:

a charged atom (has more or less electrons than a neutral atom)

Mixture:

a group of two or more elements and/or compounds that are chemically or physically intermingled

How can mixtures be separated?

mixtures can be physically separated; atoms in compounds can only be separated by chemical means (reactions)

what is an example of a mixture separating?

NaCl dissolved in H2O is a mixture. the salt can be physically removed from the water (such as by distillation of the water), but the Na+ and Cl- ions can only be separated by chemical means from each other. Likewise the H and O atoms can only be separated from each other by chemical means

Compound (differences between):

mass ration of atoms in a compound is fixed (CO2 always contains 2 oxygens for every carbon) because they are chemically bonded and atoms can not be physically separated in compounds

Mixture (differences between):

mass ratio of elements or compounds in a mixture can change (salt water: mass ratio of NaCl and H2O can change depending on how much slat is present); elements/compounds can be physically separated from each other in a mixture

the atom is an...

electrically neutral, spherical entity composed of a positively charged central nucleus surrounded by one or more negatively charged electrons

# protons=

# electrons for neutral atoms but not equal for ions

The atomic nucleus consists of...

protons and neutrons. Most of the mass is in the nucleus, but most of the volume results from the electron cloud

this means the what is much, much, much more dense than the overall atom?

nucleus

X=

atomic symbol of the element

A=

mass number; A=Z+N

Z=

atomic number (the number of protons in the nucleus)

N=

number of neutrons in the nucleus

mass number is a...

number and not a mass

Isotopes:

are atoms of an element with the same number of protons, but a different number of neutrons

Isotopes have the same what number, but a different what number?

atomic number, mass number

all elements exist as what?

as mixtures of different amounts of isotopes

why do certain isotopes exist?

because they can. Nuclear stability (physics)

Elements in what have common properties?

groups (columns)

Columns=

groups

rows=

periods

ionic compound:

results from transferring electrons from the atoms of one element to those of another. This frequently occurs when metals react with non-metals. (exception: some transition metals form covalent bonds to non-metals, such as MnO4-)

ions are...

charged single atoms or charged combination of atoms (polyatomic ions)

Na+ is a...

cation because it's a positive ion. It has one less electron than neutrally charged sodium atom

Cl-is an...

anion because it's a negative ion. It has one more electron than neutrally charged chlorine atom

metal + non-metal=

ionic compound

what can you use to predict how many electrons an element will gain or lose in forming anionic compound?

group number

atoms will attempt to gain or lose electrons depending on what?

their proximity to the nearest noble gas

atoms want to have what?

the same number of electrons as the highly stable noble gas; it makes them happier!

Covalent bonds form when elements...

share electrons, which usually occurs when non-metals bind to non-metals

some elements occur as covalently-bonded molecules instead of as...

single atoms

the diatomic, tetratomic, and octatomic molecules exist as molecules because...

they are "too" reactive to exist as single atoms in nature

molecule-

the basic unit of an element or covalent compound, consisting of two or more atoms (same or different atoms) bound together by the sharing of electrons; most covalent substances consist of molecules

ion-

a single atom or covalently bonded group of atoms (polyatomic ions) that has an overall electrical charge

there are no molecules in an...

ionic compound; but an ionic compound is still neutral in charge

NaCl (Na+Cl-)=

ionic compound, not ionic molecule

Are molecules present in a sample of BaF2?

No because BaF2 is a compound made of atoms bounded by ionic bond. Since Ionic bond is formed between cations and anions, there are only ions, no molecules

are ions present in a sample of P4O6?

no because P4O6 is a compound made of non-metal atoms and is made by covalent bonds. There are no ions in covalent bonds, only have molecule and the electrons are shared. So, there ar enough ions in this sample.

A chemical formula consists of:

element symbols with numerical subscripts

the chemical formula indicates the...

type and number of each atom present in the smallest unit of a substance

compounds must be what?

neutral in charge, so number of positive charges from cations must equal number of negative charges from anions

chemical formulas for ionic compounds:

the metal comes first, and the overall charge must equal zero; sodium chloride exist as Na+ Cl-, we write the formula as NaCl; but for Mg2+ we need 2 Cl- to give a neutral compound we write the formula as MgCl2; may use "crisscross rule" to predict formula

Naming binary (two elements) ionic compounds:

for all ionic compounds, the name and formula lists the cation first and the anion second. In a binary ionic compound, both the cation and the anion are monatomic; the name of the cation is the same as the name of the metal. many metal names end in -ium. the anion is named by adding the suffix -ide to the root of the nonmetal name; calcium and bromine form calcium bromide (CaBr2)

Charge +1

H+ (hydrogen), Li+(lithium), Na+(sodium), K+(potassium), Cs+(cesium), Ag+(silver)

charge +2

Mg2+(magnesium), Ca2+(calcium), Sr2+(strontium), Ba2+(barium), Zn2+(zinc)

charge +3

Al3+(aluminum)

Charge -1

H-(hydride), F-(fluoride), Cl-(chloride), Br-(bromide), I-(iodide)

charge -2

O2-(oxide), S2-(sulfide)

charge -3

N3-(nitride), P3-(phosphide)

An acid is a substance which generates what?

hydrogen ion (the cation: H+) when dissolved in water

Binary acid:

solutions form when certain gaseous compounds dissolve in water. ex: when gaseous hydrogen chloride (HCl) dissolves in water, it forms a solution called hydrochloric acid

HCl(g)=

hydrogen chloride

HCl(aq)=

hydrochloric acid

g=

gas state of matter

aq=

aqueous

a polyatomic ion consists of...

two or more atoms covalently bonded together and does have an overall charge

in most reactions the polyatomic ion will....

remain together as a unit

all compounds containing polyatomic ions are...

ionic compounds, even though the bonds within the polyatomic ion itself are covalent

CH3COO-

acetate

CN-

cyanide

OH-

hydroxide

CO32-

carbonate

HCO3-

hydrogen carbonate (bicarbonate)

NO3-

nitrate

O22-

peroxide

SO42-

sulfate

NH3/NH4+

ammonia/ammonium

OH-/H2O/H3O+

hydroxide/water/hydronium

HNO3

nitric acid

H2SO4

sulfuric acid

CH3CO2H

acetic acid

HCN

hydrogen cyanide

H2O2

hydrogen peroxide

a binary covalent compound is typically formed by the combination of two

non-metals

the element that is second is named using the root with what suffix?

-ide

numerical prefixes indicate?

the number of atoms of each element present

H2O (naming):

dihydrogen monoxide (water is trivial name)

Don't use "mono" for...

first element, only for second one if needed CO=carbon monoxide

the element with the lower group number in the periodic able is the...

first in the name and formula. its name remains unchanged exception: oxygen +halogen, the halogen is named first, Cl2O: dichloride monoxide

carbon monoxide is CO and

NOT oxygen carbide (OC)

when elements are in the same group what goes first?

the higher period number goes first SO2 is sulfur dioxide; ICl3 is iodine trichloride

what is the name of SF3:

sulfur trifluoride

what is the formula for phosphorous pentachloride

PCl5