Chemistry Review Flashcards
How do you find the number of neutrons?
Mass number subtracted by the protons
What is the nucleus made up of?
Neutrons and protons
What must an atom have to remain neutral?
Equal number of protons and electrons
How do you find the mass number?
Add the protons and the neutrons
What is an Isotope?
Atoms of the same element but different number of neutrons
What is Atomic mass?
This is the weighted average of various isotopes
Bohr Rutherford diagrams
A nucleus surrounded by orbitals is useful because it helps show the visualization electrons orbiting a nucleus
Looks like a planet surrounding my orbitals
Lewis dot diagram
show the bonding between atoms of a molecule by only showing the valence electrons
What happens when atoms lose electrons?
they become positively charged and turns into a cations
What happens when atoms gain electrons?
they become negatively charged and turns into a anions
what is a covalent bond?
a bond that usually exists between elements that are nonmetal when two atoms share electrons for example water
what are ionic bonds?
chemical formed between oppositely charged elements
for example sodium and chlorine
what is a molecular formula?
a formula stating the number of atoms in each element
what is a structural formula?
a drawing of atoms connected by chemical bonds
lines connecting the symbols of elements
what are structural isomers?
molecules that have the same molecular formula, but have a different arrangement of the atoms in space
what is the hill system?
using the acronym CHNOPS to write the molecular formula
what are orbitals?
a mathematical region around a nucleus that may contain electrons
what are energy levels?
Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found
what are valence electrons?
an electron in the outermost shell of an atom that can form chemical bond with another atom
what is electronegativity and what is its trend on the periodic table/
it is the ability of an atom to attract electrons
it increases moving right and up
decreases moving left and down
fluorine is the most electronegative element
what is a non polar covalent bond?
when electrons are shared equally between two atoms
this is usually seen with diatomic molecules
polar covalent bond?
when two atoms share electrons unequally
what is the meaning of hydrophilic?
elements that dissolve in water ionic compounds such as salt
what is the meaning of hydrophobic?
elements that don’t dissolve or repel water such as oil
how are ionic compound formed?
when there is a complete transfer of an electron in a bond
what is polarity dependent on?
the electronegativity of an atom and the molecular shape whether it it is asymetricalorsymetrical
what does it mean if a molecule is asymetrical?
the molecule is nonpolar if all the bonds are nonpolar
or the molecule is polar if at least one bond is polar
what determines the chemical behaviour of an atom
the number and arrangement of the atom’s valence electrons
what are the steps of making a Bohr Rutherford diagram?
- draw the nucleus with the proton and neutron numbers inside
- place the electrons on their energy levels
