U3 Part 2 Test Flashcards
Coulombs Law
F: force
K: constant
q: charge
r: distance
Like charges repel, unlike charges attract
Larger charges and a shorter distance between 2 particles = a stronger force
Smaller charges and a longer distance equal a weaker force
Atomic Radii
Half of the distance between the nuclei of 2 touching atoms
Measured in picometers
Atomic Radii Trend
left to right, size of atom decreases because more protons make attraction between nucleus and VE stronger, making a smaller distance between them.
top to bottom, size of atom increases as more orbitals are added increasing the distance
Ionization Energy (IE)
the energy required to remove high energy electrons from a gaseous atom
first IE: the energy required to remove VE from an atom
IE is endothermic because energy is needed to remove electron
IE trends
from left to right IE increases because based on Coulombs law, the increased proton numbers strengthens the attraction btw nucleus and VE, thus taking more energy to remove the VE
from top to bottom IE decreases because based on Coulombs law, the larger distance between the VE and nucleus weakens the attraction btw them, thus taking less energy to remove the VE
Electronegativity (EN)
The tendency of an atom to attract shared electrons to itself when forming a chemical bond
It can tell us if a bond is ionic or covalent
EN trends
from left to right, EN increases because more protons means stronger attraction btw nucleus and electrons making a higher EN
from top to bottom, based on coulombs law EN decreases because the larger size of the atom makes a smaller, weaker attraction btw nucleus and VE
Why is there no EN for noble gases
because EN is measured when bonds are formed and since noble gases are non-reactive (can’t form bonds), they don’t have an EN value.
Covalent bonds
made of nonmetals, share electrons, prefixes show exact # of atoms in molecule
Rules for naming Covalent Compounds
- name of the element farther to the left (closest to metals) is written first (less electronegative)
- if both elements are in the same group, the one closer to the bottom of the table is named first (less electronegative)
- Name of second element is given an -ide ending
- Greek prefixes indicate number of atoms of each elements (the prefix mono is NEVER used with the first element).
- When the prefix ends in a or o and the name of the second element begins with a vowel, drop the prefix vowel
- There are 3 covalent compounds that don’t follow these rules, and you need to memorize them.
What is the formula for ammonia?
NH3
What is the formula for hydrogen peroxide?
H2O2
What is the formula for water?
H2O
Ductile
can be stretched without snap
malleable
can be reshaped without breaking
