TEN: Chapter 1- Development Of The Atomic Theory

Question 1

Atom

Answer 1

Smallest part of an element that still has the properties of the element
They are neutral since the number of electrons equals the number of protons
Majority of their mass is of neutrons and protons since they are in the nucleus

Question 2

Why has the design of the atom changed over the last several centuries?

Answer 2

Technological advances

Question 3

The five classic models of the atom

Answer 3

The dalton model
The Thomson model
The Rutherford model
The Bohr model
The electron cloud model

Question 4

The dalton model

Answer 4

John dalton believed all atoms were like small spheres but with different properties from each other (size, mass, colour)
All the atoms of an element are identical in properties
Billard ball model
Beloved them to be indivisible

Question 5

The Thomson model

Answer 5

Discovered the electron
Was experimenting with beans of parties produces in a vaccine tube which showed the particles were negative
By testing many elements he showed they all produced the same beam
Believed the atom was a positive sphere with electrons embedded in it
Raisin bun model or plum pudding model

Question 6

The Rutherford model

Answer 6

Discovered the nucleus
Directed alpha particles at a thin sheet of gold foil and predicted that all the particles would pass through, however a few bounced and a few weeks sharply deflected
Atom is a mainly empty space but with a tiny positive core (nucleus) atoms move though the rest of the atom
Nuclear model

Question 7

The Bohr model

Answer 7

Proposed that electrons surrounded the nucleus in specific energy levels
he found evidence for those energy levels by examining the light released by the hydrogen atoms when they’re made to glow in a tube

Question 8

The electron cloud model

Answer 8

Based on quantum mechanics. It uses probabilities to describe how electrons exist in atoms. Each electron can be thought of as a cloud of negative charge. Rather then the electron acting as a small particle moving through space, instead electrons occupy the whole space all at once at different energy levels.

Question 9

Why is the word atom a misnomer?

Answer 9

“A” is a negative prefix and “Tom” means to divide, thus “Atom” means indivisible

Question 10

Electron

Answer 10

Negatively charged particle in the atom that occupies energy levels around the nucleus
Symbol: e-
Location: outside the nucleus
Charge: -1

Question 11

Proton

Answer 11

Positively charged particle in the nucleus of the atom
Symbol: p+
Location: in the nucleus
Charge: +1

Question 12

Neutron

Answer 12

Neutral particle in the nucleus of the atom
Symbol: n•
Location: in the nucleus
Charge: 0

Question 13

Which one is larger, the proton or the neutron?

Answer 13

They both are simplified to have the same mass… But a neutron is larger in the overall decimal of the kg
Also. Neutron has both an electron and a proton in it, therefor having more mass than just a proton

Question 14

What defers each element in the periodic table? And how many are there?

Answer 14

Their melting points, boiling points, electrical conductivity, reactivity, hardness, state and density
There are 118 known elements
Only 25 are pure, the rest ate compounds
There are about 90 naturally occurring elements

Question 15

Atomic number

Answer 15

The number of protons and electrons in the atom, that can be used to specify an element

Question 16

Atomic mass

Answer 16

Integer number equal to the total number of protons and neutrons in the nucleus of an atom
Decimal number (full actual number, not simplified)
Due to percentage of each isotope

Question 17

How to calculate neutrons

Answer 17

Atomic number equals protons and electrons
Atomic mass goes on top, atomic number goes on bottom, beside the symbol for the element on the left side
Minus the atomic number from the mass to calculate

Question 18

Main Subatomic particles

Answer 18

Electrons, protons, neutrons

Question 19

Bohr atom drawings: energy level diagrams (circles)

Answer 19

Bohr diagrams (circles)
Energy level diagrams: region of space near an atoms nucleus that may be empty or may contain electrons
The electrons nearest to the nucleus have the least energy
Level 1: 2 electrons
Level 2: 8 electrons
Level 3: 8 electrons
Electrons cannot exist between levels… When they change, they either release energy (going from high-low) or absorb energy (going from low-high)
Elements are most stable when their valence ring is filled, otherwise they will want to bond with other elements to fill the outer energy levels

Question 20

Lewis dot diagrams

Answer 20

Representation of valence electrons only
Gives some info if the geometry shape of compounds when used for bonding diagrams
Uses dots around the elements symbol

Question 21

Elements are arranged in the periodic table in 4 patterns

Answer 21

Atomic number
Staircase line- speeches metals from nonmetals, metals to the left and non to the right
Vertical columns- called groups or families. These are 18 groups and members of each group, that share properties although their intensity may vary
Horizontal rows- these are called periods. Elements in the same period have the same number of electron shells, with each group across a period, the elements have one more proton and electron than the last and become less metallic

Question 22

Properties of metals

Answer 22

Lustrous 
Usually solids (except Mercury)
Good conductors of heat and electricity 
Malleable and ductile
Have 1-3 electrons in the outer shell
Lose electrons easily

Question 23

Properties of nonmetals

Answer 23

Not lustrous 
May be solid, liquid or gas at room temp
Poor conductors of electricity and heat
Not ductile and are brittle solids
Usually have 4-8 electrons in their outer shell
Readily gain or share valence electrons

Question 24

Metalloids

Answer 24

A chemical element with properties that are between those of metals and nonmetals
Those commonly referred to as Metalloids, include those lining the staircase line on the periodic table

Question 25

groups of elements

Answer 25

Left to right:
Alkali metals (first group)
Alkaline earth metals (second group)
Transition elements 
Metals below the staircase line 
Metalloids lining the other side of the staircase line
Non metals above the Metalloids 
Halogens (2nd last group)
Noble gases (last group)
Below: top- lanthanide series
Bottom: actinide series

Question 26

3 ways in which an alkali metal is different then a halogen

Answer 26

Alkali metals are the most reactive and halogens are not
Alkali metals are metals and halogens are non mentals
Halogens can be gases, liquids and solids whereas alkali metals are only solids

Question 27

How do you change the mass of an atom?

Answer 27

Change the neutrons by adding or subtracting them

Electrons are too small to make a difference, and protons would change the element itself into a new one!

Question 28

Isotope

Answer 28

Atoms of the same element containing a different number of neutrons
Use the number next to the element as the mass number… If element is unknown use the mass number to find on the table

Question 29

Mass number

Answer 29

Simplified atomic mass

Question 30

Symbols for atomic mass and number

Answer 30

Z: atomic number
A:atomic mass