Chapter 4 - Atoms and Elements

Question 1

Atoms

Answer 1

• smallest identifiable unit of an element

- makes up matter

Question 2

Element

Answer 2

subctance that cannot be broken down

Question 3

Chemical Bonds

Answer 3

joins elements

Question 4

Dalton’s Atomic Theory

Answer 4

1 each element is composed of tiny indestructible particles called atoms
2 all atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements (UNTRUE)
3 atoms combine in simple whole-number ratios to form compounds

Question 5

MOLECULES

Answer 5

only 2 or more atoms joined together

Question 6

Compounds

Answer 6

2 or more different atoms

-all compounds are moles but not all moles are compounds

Question 7

subatomic particles

Answer 7

electron, proton, neutron

Question 8

Plum Pudding Model Theory

Answer 8

• suggested by JJ Thomson
• electrons are embedded into a cake-like cake/pudding
• later proved wrong

Question 9

Rutherford’s Nuclear Theory of an Atom

Answer 9

• tiny particles called alpha-particles were directed at a thin sheet of gold foil
• most of the particles passed directly through the foil via deflection (sometimes at sharp angles)

MEANING: inside an atom is something dense (nucleus) in which particles hit it and ricochet. surrounding the nucleus are free space in which electrons move around.and particles pass through.

Question 10

Atomic Number

Answer 10

• number of Protons which identifies the element

- represented by the letter Z

Question 11

Metals

Answer 11

• LEFT side of the periodic table
• tend to LOSE electrons
• good conductors of heat and electricity
• malleable
• ductile
• often shiny

Question 12

Nonmetals

Answer 12

• UPPER- RIGHT side of the periodic table
• tend to GAIN electrons
• some are solid, some are gases
• O, N, Cl, I

Question 13

Metalloids or Semimetals

Answer 13

• along the zigzag portion of the periodic table
• semimetals - displays mixed properties
• SEMICONDUCTORS bc intermediate conductivity which can be changed and controlled
• used in electronics often

Question 14

Main Group elements

Answer 14

• contains both metals + nonmentals
• has predictable properties based on their position in periodic table
• 1A, 2A, 3A-8A

Question 15

Transition Metals/Elements

Answer 15

middle area of periodic tables

-columns labeled by number and letter B

Question 16

Alkali Metals

Answer 16

1A

• very reactive
  ex) Na and K

Question 17

Alkaline Earth Metals

Answer 17

2A

• reactive
  ex) Ca, Mg

Question 18

Halogen

Answer 18

7A

-very reactive nonmetals bc wants to fill in the 1 open space

Question 19

Noble Gases

Answer 19

8A

-content/stable; full orbitals; wont bond w other elements to form compounds

Question 20

Cations

Answer 20

positive ions (usually metals)

Question 21

Anions

Answer 21

neg ions (usually nonmetals)

Question 22

Ions

Answer 22

in chem rxn, atoms often lose or gain electrons to form charged particles

Question 23

Ion Charge

Answer 23

ion charge = (#protons+) - (#electrons-)
ion charge = #p+ - #e-
ex) Li has 3 p and loses 2 e: ion charge =3-2=1+
ex)F has 9 p and gained 1 e (9+1=10) ion charge =9-10=1-

Question 24

Isotopes

Answer 24

• atoms w same number of protons but diff. number of neutrons
• ALL elements have their unique percent of NATURAL ABUNDANCE of isotopes
  ex) Neon has 10 protons but can have 10, 11, or 12 neutrons.

Question 25

Isotope Symbol

Answer 25

A (p + n) CHEM.SYMBOL.
Z (p)

or CHEM.SYMBOL- A (p+n)

ex) 20/10 Ne or Ne-20

Question 26

Polyatomic Ions

Answer 26

one type of compound that is charged

Question 27

Polyatomic Ions

Answer 27

one type of compound that is charged

Question 28

Nuclear Theory of an Atom

Answer 28

1 most of the atom’s mass and all of its positive charge are contained in a small core called NUCLEUS
2 most of the volume of an atom is empty space w electrons dispersed
3 there are neg charged electrons outside of the nucleus and protons inside the nucleus so ATOMS ARE NEUTRAL

Question 29

Atom’s Nucleus

Answer 29

makes up 99.9% of atom’s mass

-contains protons and neutrons

Question 30

Atomic Mass Unit

amu

Answer 30

• defined as 1/12 the mass of carbon containing 6 protons and 6 neutrons
• mass of proton and neutron are nearly identical
• it is an average mass of an element’s atom since diff isotopes vary in weight

Question 31

mass of proton

Answer 31

1.672 x 10^-27kg

Question 32

mass of neutron

Answer 32

1.674 x 10^-27kg

Question 33

Chemical Symbol

Answer 33

A 1 or 2 letter abbreviation for the element

Question 34

malleability

Answer 34

ability to be pounded to flat sheets

Question 35

ductility

Answer 35

ability to be drawn into wires

Question 36

Family or Group of Elements

Answer 36

-each column within the periodic table

Question 37

Percent Natural Abundance

Answer 37

• for a given element, the relative amounts of each isotope in a naturally occurring sample of that element are always the same
  ex) in any natural sample of Neon, 90.48% has 10 neutrons, 0.27% has 11 n, and 9.25% has 12 n

Question 38

Atomic Mass formula

Answer 38

atomic mass = (%xisotope mass) +(%xisotope mass) and so on

ex) Cl has 75.7% Cl-35 (mass is 34.97amu), 24% Cl-37 (mass 36.97amu)
atomic mass=(0.7577x34.97amu) + (0.2423x36.97amu)
=35.45amu

Question 39

Isotopes vs Ions

Answer 39

ions differ in electrons

isotopes differ in neutrons