Unit 2 Flashcards
What is an element
a substance that consists of identical atoms
what is a compound
a pure substance made up of two or more elements in a fixed ratio by mass
what is a mixture
a combination of two or more pure substances
atomic number ( z #)
the number of protons in the nucleus
mass number (A)
the sum of the number of protons and neutrons in the nucleus
properties of a proton
+1 charge
mass = 1.6726 x 10^-24
mass (amu) = 1.0073
in the nucleus
properties of an electron
-1 charge
mass = 9.1094 x 10^-28
mass (amu) = 5.4858 x 10^-4
outside the nucleus
properties of a neutron
0 charge
mass = 1.6749 x 10^-24
mass (amu) = 1.0087
in the nucleus
What are atoms called that have the same number of protons but a different number of neutrons?
isotopes
When something is written like Element - #, what does the number stand for ?
the mass number (protons + neutrons)
how many neutrons are in Oxygen - 16 ?
Oxygen has 8 protons, so 8 neutrons (when answering rewrite with mass number on top, protons on the bottom and the element on the far right.
What is atomic weight?
a weighted average of the masses (in amu) of its isotopes found on earth
What is the bottom number of an element on the periodic table?
the atomic mass (amu)
What is the top number of an element on the periodic table?
the atomic number (Protons)
Which elements occur naturally as only one isotope?
Gold, Flourine, Aluminum
Atomic Radius Trend
the atomic radius decreases going from left to right across a period and increases from top to bottom in a column or family
Ion trend
going from neutral to an anion, the anion will always be bigger
For every unit of negative charge, an electron is ____
gained
For every unit of positive charge, an electron is ____
lost
If elects are in the same family or column they will have similar _____ properties because they have the same number of ____ electrons
physical/valence
Metal properties
- solids at room temperature
- conduct electricity
- form alloys
- give up electro in chemical reactions
Non-metal properties
- on right side periodic table (except Hydrogen)
- doesn’t conduct energy
- accepts electrons in chemical reactions
Metalloid Properties
- mixture of properties from metal and non metals
Distribution of electrons in shells trend
as the shells go from 1-4 the energy increases
Shell number 1 - 4, how many electrons can they hold
2, 8, 18, 32
Metalloid elements
B, Si, Ge, As, Sb, Te
Ionization energy trend
increase left to right in period / decreases top to bottom in column
Is the period horizontal or vertical
horizontal
what is a cation
a positively charged ion
Electronegativity trend
increases left to right across period/ decreases top to bottom in column
How can you determine the number of valence electrons an element has?
By the group #
The family is the same as what?
The column
What is the mass number?
protons + neutrons
What corresponds with protons?
electrons
The Big Four
C, N, O, H
The Next Seven
Ca, Cl, Mg, P, K, S, Na
What does Ca do?
Helps form bones, teeth and helps with bloodclotting
What does Cl do?
Helps with normal growth and development
What does Mg do?
Helps with muscle action
What does P do?
Helps with DNA/RNA, Storage & Tranfer
What does K do?
Regulates electrical balance
What does S do?
An essential component of proteins
What does Na do?
Helps regulate electrical balance
Trace Elements
Cr, Co, Cu, I, Fe, Mn, Mo, Zn
What is stock?
Concentrated solution
Elements in group 1A tend to __ __ electrons to form __ with a charge of __ because ___
lose/ one/ cations/ +1/ Because they want a full octet
As the radius goes from left to right, the radius gets ___
smaller
As the radius goes from top to bottom, the radius gets ___
bigger
Are Ions of period 1A and 2A with charges greater than 2 stable?
No
Elements in group 2A __ __ electrons to form __ with a charge of __
lose/ two/ cations/ +2
Elements in group 3A __ __ electrons to form a __ with a charge of __
lose/ three/ cation/ +3
Elements in group 4A __ electrons to form a __ with a charge of __
share/ neither a cation or anion/ +0
What is the ending for a cation?
ion
What is the ending for an anion
-ide ion
