Unit 1 Test Review

Question 1

What is the periodic law associated with the organization of the periodic table?

Answer 1

-elements are arranged in order of increasing atomic number
-elements with similar physical and chemical properties occur at regular intervals using this order
*DIMITRI MENDELEEV

Question 2

What are the three basic types of elements found on the periodic table?

Answer 2

Metals
Non-metals
Metalloids

Question 3

Describe metal elements

Answer 3

state: solid except mercury
physical properties:
-hard, lustrous
-good conductors of heat and electrical current
-malleable and ductile

Question 4

Describe non-metals

Answer 4

state: many gas, some solid, one liquid (bromine)
physical properties:
-non-lustrous
-poor conductor of electrical current and heat
-brittle and non-ductile

Question 5

Describe metalloids

Answer 5

state: all
physical properties:
-good conductors of electrical current
-poor conductors of heat
-brittle

Question 6

What is a period?

Answer 6

-a horizontal row on the periodic table
-period number indicates the energy level (shell) of the valence electrons

Question 7

What is a group/family?

Answer 7

-vertical column on the periodic table
-group number indicates valence electron number

Question 8

What are the standard states of all elements?

Answer 8

solid
liquid
gas

Question 9

What are synthetic elements?

Answer 9

-elements that are outlined with a black border and white fill
-they are synthetically produced via nuclear fusion in nuclear reactors or particle accelerators

Question 10

In what category are most elements involved in creating living tissue found?

Answer 10

other non-metals

Question 11

Why does each period end with a noble gas

Answer 11

each noble gas has a stable amount of electrons

Question 12

What is an atom?

Answer 12

the building block of matter
make up everything but energy
-the smallest particle of an element that still retains the identity and properties of the element

Question 13

What are atoms made out of?

Answer 13

3 subatomic particles:
-neutrons
-protons
-electrons

Question 14

Explain the electron arrangement in atoms

Answer 14

-according to Borh’s diagrams, electrons exist in orbits around the nucleus
-each orbit has a specific level of energy associated with it
-the further away an electron is from the nucleus, the more energy the electron possesses
-electrons in the outermost orbit are called valence electrons, and they help form chemical bonds between atoms
-when electrons are removed, they gain a positive charge and these are called cations
-when electrons get added, these are negative and called anions

Question 15

What does it mean for an atom to be isoelectronic?

Answer 15

have the same electron count as an ion present on the periodic table

Question 16

What is the bond definition of a non-polar covalent bond, and the physical properties it may exhibit?

Answer 16

-the bond shows two elements that are shared equally because their electronegativity rates are close in amount
-the bond is then neutral through this process

physical properties:
-soft due to weak intermolecular forces
-low melting and boiling points

Question 17

What is the bond definition of a polar covalent bond, and the physical properties it may exhibit?

Answer 17

-made up of cations which have a positive charge, and anions which have a negative charge and when they bond they neutralize as opposites attract, the transfer of electrons to non-metals allows this to occur

physical properties:
-brittle
-high melting points and boiling points

Question 18

What are isotopes?

Answer 18

-atoms of one element that differ by the number of neutrons in the nucleus

Question 19

What is atomic number?

Answer 19

-the number of protons present in the nucleus of an atom
-identifies the element (different elements don’t share atomic number)
-isotopes of one element have the same atomic number

Question 20

What is mass number?

Answer 20

-the sum of the protons and neutrons present in the nucleus of an atom
-isotopes of one element have different mass numbers *NOT THE SAME AS ATOMIC MASS
-the isotopic mass number is not found by using the periodic table

Question 21

What are stable isotopes?

Answer 21

-isotopes that share the same physical and chemical properties

Question 22

What are radioisotopes?

Answer 22

-unstable isotopes as they have unstable amounts of protons and neutrons
-the nucleus is destabilized
-these unstable nuclei are radioactive, and they emit radiation through particles when they attempt to re-stabilize

Question 23

What are the three types of radiation?

Answer 23

-alpha, beta, gamma

Question 24

What are the uses of radioisotopes?

Answer 24

agriculture: added to fertilizer
food preservation: slows down spoilage
medicine: disease treatment
electricity generation: nuclear power plants
archeology: carbon dating

Question 25

How do you determine the subatomic particle counts for the isotopes of atoms?

Answer 25

number of protons: atomic number number of electrons when neutral: the same as the atomic number number of neutrons: mass number - atomic number

Question 26

How do you represent an isotope in atomic notation?

Answer 26

mass number X atomic number

Question 27

How do you represent an isotope in isotopic notation?

Answer 27

X-mass number

Question 28

What is isotopic abundance?

Answer 28

-the amount of a given isotope of an element that exists in nature, expressed as a percentage of the total amount of the element -the average atomic mass which appears on the periodic table is a weighted average that factors in the mass of all the naturally occurring stable isotopes to their percentage abundance

Question 29

What is the equation for calculating the weighted atomic mass of a naturally occurring isotope?

Answer 29

wam = (% isotope #1 x mass isotope #1) + ((% isotope #2 x mass isotope #2) +.... percentage expressed as decimal, divided by 100!

Question 30

What is the atomic radius?

Answer 30

-the approximate distance from the centre of the nucleus to the the approximate outer boundary of the cloud-like region of its valence electrons

Question 31

Describe the trend of atomic radius as you travel up and down a group

Answer 31

atomic radius INCREASES DOWN a group WHY? -moving down a group, each subsequent element has one additional orbit thus the valence electrons are further away from the nucleus -further away from the nucleus, the valence electrons experience less attractive forces from the nucleus

Question 32

Describe the trend of atomic radius as you travel from left to right across a period

Answer 32

atomic radius DECREASES ACROSS a period WHY? -the number of protons in the nucleus increases so the nucleus gets stronger and pulls the outer electrons closer

Question 33

What is an ionic radius?

Answer 33

the radius of the stable ion of an atom

Question 34

What is the trend when comparing a neutral atom to a stable ion?

Answer 34

cations: removal of electrons (+ charge) -have a smaller radius than a neutral atom because there is one less orbit so the valence electrons are now closer to the nucleus anions: adding of electrons (- charge) -anions have a larger radius than those of a neutral atom because the nuclear charge stays the same however the gaining of electrons makes the repulsive forces increase (enlarged electron cloud)

Question 35

What is first ionization energy?

Answer 35

the energy needed to remove a valence electron from a neutral atom to form a positive charge

Question 36

What is the trend associated with the first ionization energy when you travel down a group?

Answer 36

first ionization energy decreases down a group -attraction between the nucleus and electrons in the valence shell decreases down a group because atomic radius increases, meaning that less energy is needed to pull an electron away from the atom

Question 37

What is the trend associated with the first ionization energy when you travel across a period?

Answer 37

first ionization energy increases across a period -attraction between the nucleus and electrons increases as the atomic radius decreases, causing more energy to be needed to remove an electron and pull it away from the nucleus

Question 38

What is electron affinity?

Answer 38

-the ease at which an atom can add a valence electron into its outer orbit to form a negatively charged ion

Question 39

What is the trend associated with electron affinity (electro negativity) when you travel down a group?

Answer 39

electronegativity decreases down a group -since atomic radius increases down a group the attraction between the valence electrons and the nucleus decreases, thus the ability to attract electrons into its outer orbit also decreases

Question 40

What is the trend associated with electron affinity (electro negativity) when you travel across a period?

Answer 40

electronegativity increases across a period -since atomic radius decreases across a period the attraction between the valence electrons and the nucleus is stronger, thus the ability to pull in electrons into the outer orbit and attract them increases

Question 41

What do Lewis dot symbols show?

Answer 41

-the element symbol with valence electrons represented

Question 42

What are the basics of chemical bonding?

Answer 42

chemical bonds form when atoms transfer or sharing valence electrons -atoms bond with other atoms to achieve stability -chemical stability is achieved when the valence shell of an atom is full, equal to the electron count of the nearest Noble Gas -a stable valence shell is either 8 or, for a few elements, 2 electrons -a full valence shell of electrons lowers the overall energy of the atom and thus provides it with stability -when atoms/ions share the same electron configuration they are said to be isoelectronic

Question 43

What are intramolecular bonds?

Answer 43

Intramolecular bonds form between atoms within a molecule or compound.

Question 44

What do ionic bonds consist of when they chemically bond?

Answer 44

electrons are transferred from one atom to another -forms between a metal and a non-metal -metal atoms easily lose electrons and become CATIONS as they are left with an overall positive charge -nonmetal atoms easily gain electrons and become ANIONS as they are left with an overall negative charge -the cation and anion are strongly held together by electrostatic forces of attraction (opposite charges attract) -the overall bond remains neutral since the ion charges cancel each other out -referred to as ionic compounds made up of formula units

Question 45

What do covalent bonds consist of when they chemically bond?

Answer 45

-electron pairs are shared between two non-metals -called molecular compounds

Question 46

What is a polar covalent bond?

Answer 46

electrons are shared unequally -the shared electron pair spends more time closer to the atom with the greater electronegativity (greater attraction for the electrons) causing the more electronegative atom to develop a slightly negative charge while the less electronegative atom in the bond is left with a slightly positive charge

Question 47

What is a non-polar covalent bond?

Answer 47

electrons are shared equally -both atoms involved in the bond have essentially the same electronegativity (degree of attraction for shared pair of electrons) -the bond is neutral

Question 48

What is electronegativity?

Answer 48

-the relative ability of an atom to attract a shared electron pair when bonded -the type of bond that forms between two atoms can be determined by calculating the electronegativity difference between them -metals have lower electronegativity as they lose electrons -non-metals have greater electronegativity as they gain electrons

Question 49

How do you determine what bond forms between two atoms when labelling them as polar, non-polar, or ionic?

Answer 49

ELECTRONEGATIVITY SCALE -less than 0.4 then the bond formed is nonpolar covalent -between 0.4 to 1.7 then the bond formed is polar covalent -greater than 1.7 then the bond formed is ionic *however regardless of electronegativity difference if a bond forms between a metal atom and a non-metal atom it is always ionic

Question 50

How do metal atoms achieve stability?

Answer 50

-Metal atoms achieve stability through chemical reactions with other atoms (namely non-metal atoms) -A metal atom reacts to achieve stability by losing one or more electrons from its valence shell, resulting in the formation of a positively charged ion (CATION)

Question 51

What is metallic character?

Answer 51

-The chemical properties exhibited by metals are dependent on howeasily they lose electrons to form positively charged ions (cations) -The easier a metal atom can lose the electrons from its valence shell the more chemically reactive it is and the more metallic character it has

Question 52

How do non-metal atoms achieve stability?

Answer 52

-Non-metal atoms achieve stability through chemical reactions with other atoms (both metal and non-metal atoms) -A non-metal atom achieves stability by gaining one or more electrons into its valence shell resulting in the formation of a negatively charged ion (ANION) or by sharing pairs of electrons with another atom

Question 53

What is a non-metallic character?

Answer 53

-The chemical properties exhibited by non-metals are dependent on how easily they draw electrons into their valence shell either through accepting via transfer or by sharing -The easier a non-metal atom can attract electrons into its valence shell the more chemically reactive it is and the more non-metallic character it has