Chemistry I Flashcards
study study study
What are Group 3-12 called
Transition Metals
How many neutrons does Lithium-9 have
6
Characteristics of Boron Group
_3__ valence electrons
__Aluminum__ is the most common element in this group
Reactive
_Solid__ at room temperature
Characteristics of Alkali Metals
_1__ valence electrons
_soft__, can be cut with a knife
_sliver__ colored
Alkali metal + water = _hydrogen gas__
what type of charge do
neutrons have
no charge
have a mass of 1 amu
purpose of Electrons
determine reactivity with valence electrons
What is Group 18 called
Noble Gasses
What are protons so important
the # of protons determines the type of atom
the proton is the identity of the atom
Use your periodic table and tell me everything you know and can determine about Potassium
Atomic #- 19
Protons- 19
Electrons- 19
Neutrons- 20
Atomic Mass- 39.098
Mass #-39
Symbol K
1 valence electron
4 energy levels
Group 1
Alkali Metal
WHy is Hydrogen placed above group1 if it is not a metal
only 1 valence electron
same as alkali metals
Electrons are in _____ outside the nuclues in an ________
energy levels
electron cloud
importance of neutrons
contribute to mass
form isotopes
Group number =
electron number in their outer most energy level (valence electrons)
Why do flowers often float on top of water and not break the surface of the water
The light weight is not strong enough to break the ST of the water
Characteristics of Oxygen group
_very__ reactive
_6__ valence electrons
_21__% of air is oxygen
Things can’t burn without oxygen
All but oxygen are _solid__ at room temperature
Isaiah is studying cesium cadmium, and radon, Which of these elements is least likely to react and why
Radon because of full valence shell
Homogeneous Mixture
A mixture in which two or more pure substances are evenly mixed
what type of charge do electrons have
negative
Electrons almost have no mass at all
____% of the mass of an atom is located in the nucleus
99.9%
What is a pure substance
cannot be broken down or separated by physical means
A student is studying calcium, a highly reactive element that humans need for strong bones. Which characteristic of calcium is most closely related to its chemical reactivity
Calcium’s 2 valence electrons determine reactivity
How to find the average number of neutrons using the average atomic mass
Round the average atomic mass found on the periodic table to the nearest whole number, then subtract the # of protons.
An atom of chlorine, chlorine-38 has 17 protons. How many neutrons are in this atom
21
Characteristics of Groups 1 & 2 of the periodic table
_very__ reactive
Outer shells (levels) are not full
Easily lose or share electrons
Element or Compound
Cl*2
element
how can you find the number of protons with the periodic table
it is equal to the number on the periodic table
Two ways of writing an isotope
element and a dash
Carbon-14
Exponent
14^C
What properties of water allow plants to transport the water throughout the plant and why
Adhesion
allows the water molecules to stick to other surfaces and molecules such as the xylem to transport the water through the plant
how to find mass number of a atom
protons + neutrons in the nucleus
Remember - protons and neutrons are the only ___subatomic particles__ that have mass that contributes to the overall mass of the atom.
how to find neutrons using the periodic table
mass number - protons = neutrons
I am a metal with one valence electron.. I have 19 electrons in energy levels. Who am I
Potassium
What are the diatomic elemts
Hydrogen
Iodine
Bromine
Oxygen
Nitrogen
Chlorine
Fluorine
Characteristics of Carbon Group
_4__ valence electrons (quite stable but still reactive)
Carbon is a nonmetal found in diamonds, proteins, fats, and carbohydrates
Contains some metalloids such as __silicon_ and _germanium__ used in computer chips
Also has some common metals such as __tin__ and _lead__
_soild__ at room temperature
Where can you find metals on the PT
left of the metalliods
examples of heterogeneous mixtures
oil and water
sand and water
cookie dough
mixutre
two or more substances physically blended together, but do not combine chemically
What groups are very reactive together and often form salts
Alkali Metals and Halogens
What is Group 16 Called
Oxygen Group
Are diatomic elements compounds or elements
Elements.
In order to be a compound, they must be 2 different elements
What is the atomic number of an element that has 6 Ve- and 3 energy levels
16
Characteristics of Noble Gasses
8 valence electrons (except _helium__ which has 2.
All are “happy” with a full outer level – no room for more electrons
_colorless__
_odorless__
_gases__ at room temperature
I am an element with 4 VE- and am in the same period as chlorine. WHo am I
Silicon
What do valence elctrons determine of an element
chemical properties and reactivity
Refer back to the water strider in lesson 2. How do the properties of water allow the water strider to walk on the surface of the water and not break through the surface
cohesion- keeps molecules together
Surface Tension- helps water maintain shape
These properties make it difficult to break the bonds of the water molecules
What is the relationship between the number of electrons and protons in an neutral atom
the number of electrons is equal to the number of protons
neutral means equal number of protons and electrons
What is the overall charge of an atom
Why?
neutral
This is because atoms have the same number of protons and electrons. Their charges cancel each other out and make the entire atom neutron
An atom of Lead-220 has 82 electrons
How many protons and neutrons are in this atom
82 protons
138 neutrons
What group is the least reactive and why
Noble Gases
they are unreactive because of their full valence shell
Heterogeneous Mixture
A mixture in which two or more pure substances are not evenly mixed
easy to see separation
How many protons does an atom with an atomic nymber of 12 and a mass of 24 have
12
What do neutrons change and dont change
neutrons only change the mass
they do no change the charge or the chemical behavior of the atom
is saltwater a hertero or homogenerous mixture
homo
A=P=E
Atomic number = # of __protons___ = # of __electrons____
The nucleus is located in the ______ of the atom
center
number of electrons based on each energy level of an atom
1st Level (closest to nucleus) – hold up to 2 electrons
2nd Level – holds up to _8_ electrons
3rd Level – holds up to _8_ or _18_ electrons
(Generally, electrons will enter _outer energy__ levels only after the inner levels are _full__.)
How many electrons can energy levels 1-3
level 1- 2
level 2- 8
level 3- 8-18
what is Group 2 called
Alkaline Earth Metals
What is Group 17 Called
Halogens
What is Group 15 Called
Nitrogen Group
What is Group 13 called
Boron Group
Characteristics of Nitrogen Group
_5__ valence electrons
Nitrogen is the only element in this groups that is a _gas__ at room temperature
It makes up _78__% of the earth’s atmosphere
Nitrogen is _unreactive___
_Phosphorous__ is SO reactive it is only found in nature combined with other elements
What type of charge is the nucleus
positive because the nucleus is made up of protons and neutrons
Electrons move around a space outside the nucleus in an ______-
electron cloud
Krypton-90 has how many protons
36
Characteristics of Halogens
_7__ valence electrons
_very__, _very__ reactive!
One needs _one__ more electron to have a complete (full) out level. They can easily gain one from the alkali metals group (group 1)
They are _never__ found in nature uncombined
_poor__ conductors of electric current
React _violently__ with alkali metals to form salts
Physical properties vary greatly
2 are __gases_; 2 are _solids__; 1 is _liquid__
Compound
A substance containing atoms of two or more different elements connected together
what type of charge do protons have
positive
they have a mass of 1 amu
What is the mass of a potassium atom with 23 neutrons
42 amu
Diatomic elements
A molecule that consists of two atoms that are the same
What are isotopes
atoms of the same element (same number of protons) with a different number of neutrons.
Remember, neutrons have no charge so having different numbers of neutrons does not change the charge of the entire atom.
Where can you find nonmetals on the periodic table
Right Side of PT
excpet hydrogen
where are neutrons located
in the nucleus
Element
A substance that consists of only one type of atom
atomic number =
number of protons
number of protons and electrons are equal
Characteristics of Transition Metals
Valence electrons number does not follow any easy rule
less likely to lose electrons
more stable elements
All are __metals_
Shiny
Good conductors of _thermal___ energy and _electric__ current
_higher__ density
High melting point (except Mercury) than groups 1 & 2
what are valence electrons
electrons in the outermost energy level of an atom
characteristics of Alkaline Earth Metals
two valence electrons
_reactive__ but less reactive than group 1
more stable; don’t lose electrons as easily
_silver__ colored
more dense than alkali metals
What group of elements has properties of both metals and nonmetals
metalloids
What is Group 14 called
Carbon Group
What is group one called
Alkali Metals
An atom with 82 protons, 82 electrons, and 130 neutrons has a mass number of what
212 AMU
where are electrons located
outside the nucleus
these circle the nucleus of the atom
where are protons located in the atom
in the nucleus
