Atoms, Moles Etc Flashcards
What is an isotope?
Atoms of a single element (same atomic number) that differ in the number if neutrons in their nuclei (different masses)
What is the mass number?
The combined number of protons and neutrons in a nucleus
Different isotopes have the same chemical properties, explain why
Chemical properties depend on the number of outer electrons, so are the same in each isotope.
Define the term relative atomic mass
The weighted mean mass of an atom of an element compared to 1/12 the mass of a C-12 isotope.
What is the formula for hydrochloric acid?
HCl
What is the formula for nitric acid?
HNO3
What is the formula for sulfuric acid?
H2SO4
What is the formula for ammonia?
NH4
What is the formula for sodium hydroxide?
NaOH
What is the formula for potassium hydroxide?
KOH
What is an acid?
All acids contain the element hydrogen. When an acid is added to water, the acid releases hydrogen ions into the solution.
What is a base?
A base is the opposite of an acid:
Bases accept the protons , bases neutralise acids.
What donates protons?
An acid
Give some examples of bases.
Metal oxides, metal hydroxides, ammonia, amines
What is an alkali?
An alkali is a base that dissolves in water forming hydroxide ions. A soluble bass.
What do alkalis release when added to water?
OH ions
What is a salt?
A salt is a chemical compound produced when a H+ ion from an acid is replaced by a metal positive ion or an ammonium ion NH4+
Acid + Alkali
Salt + water
Acid + base
Salt + water
What happens in a salt reaction?
The solid dissolves in the liquid
What happens when an acid reacts with a carbonate?
Salt + water + carbon dioxide
What happens when a metal reacts with an acid?
Salt + hydrogen
What is the state symbol for salts?
Aq
What is formed when acids are neutralised by aqueous ammonia?
Ammonium salt
Whose model of the atom is the closest to accurate?
Bohr
What are the four principles of the Bohr model?
- Electrons can only exist in fixed orbits or shells and not anywhere in between
- Each she’ll has a fixed energy
- When an electron moves between shells electromagnetic radiation is emitted or absorbed
- Because the energy of shells is fixed, the radiation will have a fixed frequency.
Define the term ‘first ionisation energy’
The energy required to remove one electron from each atom in one mole if gaseous atoms to form 1 mole of gaseous 1+ ions
Define ‘ionic bond’
A chemical bond formed between two ions with opposite charges. Ionic bonds form when on atom gives up one or more electrons to another atom. These bonds can form between a pair of atoms or between molecules and are the type of bond found in salts.
Define covalent bond
The bond formed by the sharing if a pair of electrons by two atoms.
Define electronegativity.
The measure of ability of an atom or molecule to gain or lose an electron to form ions.
What is the atomic number of an element?
The number of protons in a nucleus, the number of electrons in a neutral atom
In group 1, why is less energy needed to ionise gaseous atoms of rubidium that gaseous atoms of sodium?
They have a larger atomic radius, more shells and more shielding so the electrons on the outside are further away from the nucleus and have less nuclear attraction.
What is the shape of an s orbital?
Circle
What is the shape of a p orbital?
Figure of 8
How many electrons completely fill a p sub shell?
6
How many electrons completely fill the third shell?
18
How many electrons fill a d orbital?
2
How many electrons can fill a d sub shell?
10
