Flashcards in Unit 1 - Matter, Chemical Trends & Chemical Bonding Deck (29):
What is ionization energy?
The amount of energy required to remove an electron from an atom in the gaseous state; atoms with low ionization energy easily lose electrons
What is electron affinity?
The amount of energy released when an electron is added to an atom in the gaseous state; atoms with high electron affinity will release a lot of energy to gain electrons
What's the difference between electron shells closer to the nucleus and shells further away from the nucleus?
Shells closer to the nucleus contain less energy, so more energy must be given off when an electron is added.
Valence Shell Electron Pair Repulsion Theory (VSEPR)
The shape of molecules are based on the tendency of electrons to repel one another, since electron clouds want to be the furthest possible distance from other clouds.
3 types of van der Waals (intermolecular) forces
2. (London) dispersion forces
3. hydrogen bonds
empirical knowledge vs. theoretical knowledge
Empirical knowledge comes directly from observations, while theoretical knowledge is based on ideas created to explain observations.
What is the law of conservation of mass?
law stating that during a chemical reaction matter is neither created nor destroyed; mass of reactants = mass of products
What is the law of constant composition?
law stating that compounds always have the same percentage composition by mass
Electronegativity is a number that measures the relative ability of an atom to attract bonding electrons.
Properties of ionic compounds
- solids at SATP
- high melting points
- hard, brittle
Properties of molecular compounds
- low melting points
- soft, malleable, flexible
Define binary compound.
a compound composed of two kinds of atoms or two kinds of monatomic ions (ions consisting of one charged ion)
A polyatomic ion containing oxygen (e.g. ClO3, SO4)
What is a polar covalent bond?
A covalent bond formed between atoms with significantly different electronegativities; a bond with some ionic characters
What was the gold foil experiment?
An experiment conducted by Rutherford, which involved shooting alpha particles through very thin pieces of gold foil. He found that some particles reflected instead of passing through. This lead to the discovery of the nucleus.
Define transition and ground state.
Transition - movement of an electron from one energy level to another
Ground state - the lowest energy level that an electron can occupy
What is the bonding capacity?
It is the number of electrons that are NOT part of a lone pair (imagine Lewis diagrams)
What is an isotope?
Atoms of an element with a different number of neutrons.
Properties of metals
- solids at SATP
- conductors of electricity
Properties of nonmetals
- generally nonconductors of electricity
- gases or solids at SATP
Difference between intermolecular forces and intramolecular forces
Intermolecular forces are forces between molecules while intramolecular forces are forces between the atoms and ions WITHIN a molecule
State the electron capacity of s, p, d, and f subshells.
s orbitals can hold 2 electrons
p orbitals hold 6 electrons
d orbitals hold 10 electrons
f orbitals hold 14 electrons
What are electronegativity trends and why?
Electronegativity decreases as you move down the periodic table, because there are more shells between valence electrons and the positive nucleus and atomic radius increases(attraction is less).
It increases as you move left to right because the # of shells stay the same, but there are more protons to attract electrons.
What are ionization energy trends and why?
Ionization energy increases as you move up the periodic table, because the effective nuclear charge increases, therefore it takes more energy to remove the electrons.
Generally, it increases as you move left to right, since metals generally want to lose electrons and nonmetals generally want to gain electrons (e.g. alkali metals on the left really want to lose one electron to become stable while noble gases on the right really want to keep electrons)
What are electron affinity trends and why?
Electron affinity increases as you move up the periodic table and increases as you move left to right.
What are the periodic trends for metals?
Increases as you go down, because valence electrons are more easily given away.
Decreases left to right, because there are more electrons it needs to give away
What are the periodic trends for nonmetals?
Reactivity increases as you go up, since valence shells are closer to the nucleus, making it easier to gain electrons
Reactivity increases across a row, since fewer valence electrons are required to make a stable octet
List the intermolecular forces in order of strongest to weakest.
1. Hydrogen bonds
3. London dispersion