Periodicity and Atomic Theory Flashcards

1
Q
  1. What did the early Greeks and Alchemists believe? (5th century BC)
A

-Substances are different because of size and shape
-Periodic table elements: Air, Water, Earth, Fire
-Combining moist, dry, heat and cold in diff ways you get all substances
-Came up with “atomos” (indivisible)
-In middle ages Arab & European alchemists separated metals and ores & conducted diff experiments
-Very much philosophical not experimental

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2
Q
  1. What was John Dalton’s Atomic Theory? (1808)
A
  1. Elements composed of tiny particles named atoms
  2. Elements made of atoms that are same but all made up of specific sequence of diff atoms put together in unique way
  3. No 2 chemical compounds are same but all made up of specific sequence of different atoms put together in unique way
  4. When chemical reaction happens, atoms moved around to create new compounds. New compounds created by same atoms from compound before reaction.
    -These laws agreed with preexisting laws: Law of definite Proportions, law of multiple proportions, Law of conservation of mass
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3
Q
  1. What was JJ. Thomson’s Model of the Atom? (late 1800’s early 1900s)
A

-atoms contain negative particles that have a mass
-atom is positively charged sphere with negative charges inside at random
-Plum Pudding Model

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4
Q
  1. What was Rutherford’s Model of the Atom? (1908)
A

-there are both positive and negative charged particles
-predicted neutrons
-gold-foil experiment (alpha particles) proving nucleus contains protons and heaviest part of atom

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5
Q

What was the Bohr Model? (1913)

A

-Electrons have unchangeable energies stay on a path rotating around nucelus
-Electron: outer orbit to Inner orbit = energy given off
-Electron: inner orbit to outer orbit = energy absorbed

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6
Q

What is and Ion?

A

Electrons are added or taken away from a neutral atom, an Ion is formed

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7
Q

What happens when you take away electrons?

A

Cation is formed (positive ion)

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8
Q

What happens when you add electrons?

A

Anion is formed (negative ion)

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9
Q

What is Atomic Mass?

A

The number of protons and neutrons in an atom
(atomic mass - atomic # = # of neutrons)

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10
Q

What are Isotopes?

A

Atoms having the same atomic number (same # of protons) but different atomic masses (diff. number of neutrons)

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11
Q

What is electron configuration?

A

description of which orbitals in an atom contain electrons and how many electrons are in each orbital

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12
Q

What makes a d-subshell especially stable?

A

filled or 1/2 filled

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13
Q

What is the electronic configuration for Anions?

A

Add electrons to last unfilled subshell

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14
Q

What are the rules for the electronic configuration for Cations?

A

-electrons in outermost shell (with largest number value) are removed 1st
-within shell (same number value), most energetic removed 1st

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15
Q

What does Isoelectronic mean?

A

atoms & ions having the same # of electrons

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16
Q

What are Valence Electrons?

A

-electrons that take part in chemical Rxns
-all electrons except in the core and filled d or f orbitals OR when S&P are both filled

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17
Q

How many elements were known before 1830?

A

Approx. 50

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18
Q

Who invented the periodic table?

A

Dmitri Mendeleev

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19
Q

What was Dmitri Mendeleev periodic table?

A

-listed element in order of increasing mass
-categorized elements w/ similar properties
-Was able to predict elements w/ similar properties
-Was able to predict elements unknown yet
-Discovered “The Periodic Law” using it to create periodic table
-63 elements known during his work w/ chemistry

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20
Q

What is the Periodic Law?

A

States that the physical & chemical properties of the elements recur in a systematic and predictable way when elements are arranged are arranged in order of increasing atomic #

21
Q

What is Periodicity?

A

The repeating pattern of physical & chemical properties shown by the different periods

22
Q

What is going on on the modern periodic table?

A

-organized by atomic #
-grouped based on similar # of valence electrons
-Period: elements in a row going across table
-Group/Family: elements in a column going down the table

23
Q

What are Metals?

A

Shiny (luster), metallic, good conductors, malleable, ductile, usually solid @ RT

24
Q

What are Nonmetals?

A

Gasses or liquids @ RT, poor conductors

25
Q

What are Semiconductors?

A

Have properties which resemble metals & nonmetals
[B, SI, Ge, As, Sb, Te]

26
Q

What happens to elements going across and down periodic table with metallicity?

A

Metallic - non-metallic going across (left-right) table
+ Metallic (better metals) going down a group

27
Q

What are some facts about the Alkali Metals?

A

-Silver lustre, ductile, great conductors of electricity and heat
-More reactive going down group

28
Q

What are some facts about the Alkaline Earth Metals?

A

-2+ charge, easily lose electrons

29
Q

What are some facts about the Transition Metals?

A

-look like metals, malleable, ductile, conduct heat and electricity, form positive ions.

30
Q

What are some facts about the Halogens?

A

-Highly reactive and extremely electronegative
-All fairly toxic

31
Q

What are some facts about the Noble Gases?

A

-Very stable and don’t want to react
-gasses, colourless and odourless

32
Q

Where are the Lanthanides & Actinides?

A

-F-block
-Lanthanides start with element Lanthanum
-Actinides start with element Actinium

33
Q

What happens to atomic radius going down a group? Why?

A

-Radius increases going down a group
-Electrons occupy more orbitals further from the nucleus

34
Q

What happens to atomic radius across a period? Why?

A

-Radius decreases across a period
-Force of attraction between nucleus and electrons is greater, electrons closer to nucleus

35
Q

What happens to Ionic radius down a group? Why?

A

-Radius increases down a group because more shells are added

36
Q

What are the exceptions to electronic configuration? Why?

A

-Chromiun: [Ar]4s1 3d5
-Copper: [Ar] 4s1 3d10
-Half filled d-subshell especially stable

37
Q

What happens to Ionic radius with a CATION?

A

-Size always decreases since a whole electron shell is lost

38
Q

What happens to Ionic radius with an ANION?

A

-Size always increases because more electrons with less attraction to nucleus

39
Q

What is Ionization Energy?

A

energy required to remove a mol of electrons from a mol of atoms in the gas state (KJ/mol)

40
Q

What are the three factors that affect ionization energy?

A

1)The size of an atom (atomic radius) the further away an electron is from nucleus, less attracted easier to remove
2)The shielding effect Repulsion or shielding of electrons from filled inner core orbitals repels the valence electrons
3) Effective Nuclear Charge (ENC) The charge or pull a nucleus has on an electron (more protons more + pull)

41
Q

What happens to ionization Energy going down a group? Why?

A

-IE decreases going down a group due to shielding effect at inner electrons (electrons further from nucleus attraction easier to remove)

42
Q

What happens to ionization energy across a period?

A

-IE increases across a Period (left to right)
-More protons and more electrons are added to same shell going across the period (more attraction greater ENC going across a row)
-THERE ARE EXCEPTIONS

43
Q

What is Electronegativity?

A

-An atom’s tendency to attract electrons from another atom

44
Q

Who has the highest electronegativity?

A

-Halogens (anions)
-Only need 1 more electron to be stable
-FLUORINE is the most electronegative

45
Q

Whos has the lowest electronegativity?

A

-Alkali Metals
-Do not want any electrons
-CAESIUM is least electronegative element

46
Q

What happens to electronegativity going down a group?

A

-Decreases

47
Q

What happens to electronegativity across a period?

A

-Increases

48
Q

Why is O2 lower than Nitrogen on IE graph?

A

-Nitrogen has a 1/2 filled shell making it more stable not wanting to lose electrons

49
Q

Why is Boron lower than Beryllium on IE graph?

A

-Ion is like a noble gas