Unit 1, Atoms Molecules and Ions

Question 1

Chemistry

Answer 1

-the study of chemical elements and the compounds they form
-the study of chemical reactions and the quantities of products they form

Question 2

Atoms

Answer 2

the smallest particle of an element ex. H- hydrogen

Question 3

Molecules

Answer 3

group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction

Question 4

Ions

Answer 4

a charged entity formed when an atom gains or loses one or more electrons

Question 5

Law of conservation of mass

Answer 5

-mass is neither created nor destroyed in a chemical reaction

Question 6

Law of definite proportion

Answer 6

different samples of the same compound always contains its constituents elements in the same proportions by mass

Question 7

Law of multiple proportions

Answer 7

Dalton
-If 2 elements can combine to form more than one compound, the masses of 1 element that combine with fixed mass of the other element are in ratios of small whole numbers

Question 8

Size of an atom

Answer 8

Measured in picometers (pm)

Question 9

Electrons

Answer 9

-found outside the nucleus
-negatively charged
-negligible mass

Question 10

Protons

Answer 10

-Found in the nucleus
-Positive charge equal in magnitude to the electron’s negative charge

Question 11

Neutrons

Answer 11

-found in the nucleus
-no charge
-virtually same mass as a proton

Question 12

Subatomic particles

Answer 12

make up the atom; protons, neutrons, electrons

Question 13

Cathode tube

Answer 13

-J.J Thomson (1903)
-measured deflection as stream bent towards positive field
-determined charge to mass ratio of an electron
-found out that e were neg b/c they were attracted to the positive plate

Question 14

Milikan’s oil drop experiment

Answer 14

-Robert Milikan (1909)
-combining his results with jj thomson, he found the mass of the electron to be 9.11x10^-31kg
-found the charge of a coulomb

Question 15

coulomb

Answer 15

equivalent to the charge of an object with an excess or deficit of 6.24x10^18 electrons

Question 16

Elementary charge (e)

Answer 16

the magnitude of the charge of an electron (-1e) or proton (+1e). One elementary charge= 1.602x10^-19C

Question 17

Isotopes

Answer 17

-Atoms with the same number of protons but different numbers of neutrons
-have almost identical chemical properties
-in nature, most have isotopes

Question 18

Isotopes are identified by

Answer 18

A (mass number)- number of protons plus number of neutrons
Z (atomic number)- number of protons
X- element symbol
A/Z (X)

Question 19

Calculating average relative atomic mass

Answer 19

sum of (mass x abundance)
mass- atomic mass, measured in u or amu
abundance- percentage in form of 0.xx
SIG DIG

Question 20

Covalent bonds

Answer 20

-bonds form between atoms by SHARING electrons
-resulting collection of atoms is a molecule

Question 21

Ionic bonds

Answer 21

form due to force of attraction between oppositely charged ions
form crystal lattice structure

Question 22

Ion

Answer 22

atom or group of atoms that has a net + or - charge

Question 23

Cation

Answer 23

positive ion, lost electrons

Question 24

Anion

Answer 24

negative ion, gained electrons

Question 25

Metallic bonds

Answer 25

-each electron becomes detached from its metal atom; delocalized electrons -held together by the forces of attraction between the positive nuclei and the delocalized electrons (electron sea model)

Question 26

Electron sea model

Answer 26

-positively charged ions (big) -delocalized electrons (small)

Question 27

Metals

Answer 27

-Left of staircase -good conductor of heat and electricity -solid at room temp (except Hg) -Lustrous, ductility, malleability, high melting and boiling point

Question 28

Non-metals

Answer 28

-right of staircase -poor conductor of heat and electricity -brittle -solid, liquid, gas

Question 29

Metalloids

Answer 29

-Most abundant is Si -Properties are intermediate btwn metals and non-metals -shiny or dull -solids -semiconductors -B, Si, Ge, As, Sb, Te, Po, At

Question 30

Diatomic molecules

Answer 30

exist in 2s hockey stick and puck: HOFBrINCl and At