Chemistry 1111 Chapter 2-Atoms and Molecules

What is an element?

any substance that cannot be broken down into simpler substances

What is a compound?

a substance that consists of only atoms with the same nuclear charge

What are the two broad classes elements are split into?

nonmetals, metals

What is the differences between malleable and ductile?

malleable: rolled/hammered into sheets

ductile: drawn into wires

Metals can be cast in various ___, are good conductors of ____ and ___ and are malleable and ductile

shapes, heat/electricity

nonmetals are not ____ or ___ and vary in ____. Nonmetals are ___ at room temp and are ___ conductors of heat and electricity

malleable or ductile

gasses

poor

What are the only elements liquid at room temp?

Br, Hg

What are chemical symbols?

abbreviations used to designate elements

What are some examples of elements that exist in nature as a unit consisting of 2 atoms?

Br2, Cl2, I2, N2, O2

What is a molecule?

unit consisting of 2+ atoms joined together

What is a diatomic molecule?

molecule consisting of just 2 atoms

What is the difference between oxygen and an oxygen atom?

oxygen = O

oxygen atom = O2

The only natural diatomic elements have names end in ___ or ___

-ine or -gen

What are the three states of matter?

solid, liquid, gas

Which state of matter has a fixed shape because the particles are held together in a rigid, well defined lattice?

solid

what is an example of a solid that isn't hard or rigid? What is it used for?

gold - jewelry, thin sheets

What is a solid denoted by?

italicized (s) in paranthesis after chem symbol/formula - NaCl(s)

Which state of matter has a definite volume but not a specific shape and conforms to the shape of a container?

liquid (l)

In a liquid, particles are held together but are free to do what?

move around in the volume of the liquid

What is a gas?

substance that fills the entire volume of its container and has no definite shape

In a gas, particles are widely ____ and move ____ within the volume of the gas

separated, rapidly

What is a mixture? Ex?

the component substances exist together without combining chemically - air

What is a heterogenous mixture?

not uniform from point to point - mixture of sugar, sand, iron fillings, gold dust

What happens in dissolution?

material separated from remaining components by added water (sugar)

What is a homogenous solution?

uniform to the point - made of 2+ components

What is the solute?

solid that is dissolved (sugar)

What is the solvent?

liquid that solid is dissolved in (water)

What is an aqueous solution?

forms when a substance is dissolved in water (sugar dissolved in water)

What is the filtration process?

solution passes readily through small pores in filter paper, but large particles are trapped on the paper

What is the process of evaporation?

water is evaporated and leaves the recrystalized sugar

What is distillation used for?

to separate a liquid from solid using boiling water (mercury boils away and gold remains)

What is condensation?

vapors are cooled (mercury) and converted back to liquid in a condenser

What is a volatile component?

one that is easily vaporized (liquid)

What is fractional distillation?

separation of a solution with 2+ volatile components

What is the law of the relative amount of each element in a particular compound is always the same, regardless of the source of the compound or how the compound was prepared?

law of constant composition

What is mass percentage?

how we specify the relative amounts of each element in a compound

Which law states that when a given element - X combines with another element-Y to form two different compounds, then X combines in such a way that for a fixed mass of X, the ratio of the masses of Y in the two compounds consists of small whole numbers?

law of multiple proportions

What is Dalton's atomic theory?

matter is composed of small indivisible particles called atoms

the atoms of a given element have the same ___, ____ behavior, and are ____ in all respects

mass, chemical, identical

Atoms of different elements differ in what 2 things?

mass & chemical behavior

What are composed of 2+ atoms of different elements joined together?

compound

What is the resulting particle of a compound?

molecule

in a chemical reaction, atoms involved are ____, ____, or ___ to form new substances

rearranged, separated, recombined

No atoms are created or destroyed in a chemical reaction, and the atoms themselves are NOT ____

changed

What is the atomic mass ratio?

ratio of the mass of a given atom to the mass of some particular reference atom

What is an amu?

atomic mass unit (atomic masses)

What is chemical nomenclature?

system for the assignment of names to compounds

What are binary compounds?

compounds consisting of 2 elements

How do you write a binary compound made of a metal and a nonmetal that combine in only one fixed ratio?

write name of metal, then nonmetal with the ending of nonmetal changed to -ide

What is a chemical formula?

joining of chemical symbols of the 2 elements

What does a subscript indicate?

the number of atoms (K20)

How do we name a compound that consists of 2 nonmetalic elements?

using Greek prefixes

What happens a prefix is combined with a name beginning with a vowel?

the final a or o is dropped from the prefix

What happens when H is listed first in a binary compound?

it is treated as a metal and named accordingly

When is hydrogen treated as a nonmetal?

when H is at the end of a binary compound

What is molecular mass?

sum of the atomic masses of the atoms in a molecule

Most of the atom's mass is found where?

the nucleus

What are particles called that compose an atom?

subatomic particles

What are cathode rays?

electrical discharge that were streams of identical, negatively charged particles seen flowing between metallic electrodes

What is an electron?

negatively charged particles surrounding atom's nucleus

What is a coulomb?

SI unit for charge

What is the process by which certain atoms spontaneously break apart?

radioactvity

Radiation emitted by radioactive substances consist of what 3 types?

alpha particle, beta particle, gamma rays

What is the nucleus?

center of the atom that houses the bulk of the mass concentrated in a small volume

What are protons?

positively charged particles found in atomic nucleus

What are neutrons?

neutral particles with a greater mass than that of a proton

What is atom's atomic number?

number of protons in an atom (Z)

What kind of atom has the number of electrons equal to the number of protons?

neutral atom

no two elements have the same ___ ___

atomic number

What is mass number?

total protons and neutrons in nucleus

What are atoms of one element that contain the same number of protons but different # of neutrons?

isotopes

What is deuterium?

heavier hydrogen isotope (D)

An isotope is specified by what two things?

atomic number (z)

mass number (A)

What is a naturally occurring percentages of the isotope of a particular element?

natural abundance

What is a mass spectrometer?

instrument that determines the mass and percentage of each isotope of an element

What is an ion?

atom/molecule that gains or loses 1+ e- becomes charged

What are cations?

positively charged ions

What are anions?

negatively charged ions

What is the weighted average?

the atomic mass of the element is the sum of the masses of each isotope, each multiplied by its natural abundance

What is isoelectric?

species that contain the same number of e-

How are ions denoted?

chem symbol of the element with a right hand superscript to indicate the charge

How are cations named?

element name plus the word ion or cation

How are anions named?

given -ide endings plus the word anion or ion