Flashcards in Help Deck (69)
What is a molecule?
A molecule is a group of two or more non-metal atoms joined together by covalent bonds. Examples of molecules include water oxygen methane and carbon dioxide.
What is an element?
Something that contains only one type of atom, each atom must have the same number of protons.
What all the relative masses and relative charges of protons neutrons and electrons?
Relative mass: 1
Relative charge: +1
Relative mass: 1
Relative charge: 0
Location: in the nucleus
Relative mass: 1/2000
Relative charge: -1
Location: around the nucleus
What is the atomic number?
The number of protons in the nucleus of an atom.
What is the periodic table arranged in order of?
Atomic number of the elements.
What is the mass number of an atom?
The number of protons plus the number of electrons.
What are isotopes?
Atoms of the same element with a different number of neutrons.
What is the relative atomic mass and how do you weight it?
The relative atomic mass is the weighted average mass of all the isotopes of an element.
=(isotope mass x isotope abundance)
What is the empirical formula?
The simplest hole number ratio of elements in a molecule.
How do you work out the molecular formula?
You work out the moles by doing the mass/mr then you times the empirical formula by the number of moles to get the actual number.
How do you calculate percentage yield?
Percentage yield = actual amount of product produced/theoretical amount that could be produced
X100 for a percentage.
Why do ions form?
Atoms a stable when they have a full electron shell. Atoms bond together so that they can gain or lose electrons they need to become stable.
Why do metal ions have an overall positive charge and nonmetal ions have an overall negative charge?
Metal ions have lost negative particles to become ions and nonmetal ions have gained negative particles to become Ions.
What is a redox reaction?
When both oxidation and reduction occurs.
What is an atom?
An atom is the smallest particle of an element that can exist. Atoms are made of protons, neutrons, and electrons.
What are oxidation and reduction?
Oxidation is loss
Reduction is gain
What is a covalent bond?
A shared pair or pairs of elections between two atoms.
How can you use dot and cross diagrams to show the formation of ionic compounds by electron transfer?
You draw the two elements with the first and outer shells and draw on the electrons with dots for one and crosses for the other. Then you draw the ions that will form which have squared brackets, charge signs and you give the dots to the other that needs it.
What is ionic bonding and why?
Ionic bonding is a strong electrostatic force of attraction between oppositely charged ions. The ions formed will be stable and the positive and negative ions will attract each other very strongly.
Why do ionic compounds have high melting points?
Because of strong electrostatic forces of attraction between oppositely charged ions. A lot of energy is required to break them.
In what substances does covalent bonding occur?
Non metal atoms that have too few electrons.
Draw a hydrogen covelent bond
Two H particles with one shell and one shared pair of electrons, none on the outside.
Draw chlorine covalent bond.
Two chorine, 3 shells (2,8,7) then one shared pair of electrons with the other.
Draw water covalent bonding.
Oxygen with 2 shells, 2 shared pair of electrons with different hydrogens. 4 not shared pairs in outer shell.
Draw methane covalent bond.
Two on inner shell 4 on outer shell all covelently bonded with 1 hydrogen to make 8. CH4.