Chemistry - Atoms, Bonds and Groups - F321 - Atoms and Reactions (1) Flashcards
Who first suggested the idea of the atom?
Democritus first suggested the idea of the atom.
In which century did Democritus suggest the idea of the atom?
In the 5th century BC Democritus first suggested the idea of the atom.
What does atomos mean in Greek?
In Greek, atomos means indivisible.
How did Democritus believe that atoms were held together?
Democritus believed that atoms were held together by tiny hooks.
Who proposed atomic theory?
John Dalton proposed atomic theory.
In which century did John Dalton propose atomic theory?
John Dalton proposed atomic theory in the 1800s (19th century)
What were the key points of atomic theory?
* Atoms are tiny particles that make up elements * Atoms cannot be divided * All atoms of a given element are the same * Atoms of one element are different from those of every other element
Who discovered the electron?
Joseph John (JJ) Thomson discovered the electron.
In what years were the electron discovered?
The electron was discovered in 1897-1906.
What did Joseph John (JJ) Thomson use in the discovery of the electron?
Joseph John (JJ) Thomson used cathode rays in his discovery of the electron.
How did Joseph John (JJ) Thomson propose that an atom was constructed?
Joseph John (JJ) Thomson proposed that an atom should be thought of as being made up of negative electrons swimming round in a ‘sea’ of positive charge.
What was Joseph John (JJ) Thomson’s model of the atom called?
The model which Joseph John (JJ) Thomson proposed for the structure of the atom (negative electrons swimming round in a ‘sea’ of positive charge) was called the plum pudding model.
What term did Joseph John (JJ) Thomson use for negative charges?
Joseph John (JJ) Thomson used the term corpuscle to describe negative charges.
Who disproved the plum pudding model?
Ernest Rutherford and his two students, Hans Geiger and Ernest Marsden disproved the plum pudding model.
In which year did Ernest Rutherford and his two students, Hans Geiger and Ernest Marsden, disprove the plum pudding model?
In 1909 Ernest Rutherford’s two students Hans Geiger and Ernest Marsden did work to disprove the plum pudding model.
What was the experiment conducted by Ernest Rutherford’s students Hans Geiger and Ernest Marsden in 1909 that disproved the plum pudding model?
They directed alpha particles towards a sheet of very thin gold foil and measured deflection. If the plum pudding model were true then the sheet should hardly deflect alpha particles at all. Most of the particles were not deflected at all, a very small percentage were deflected through large angles and a very small percentage were deflected back to the source.
In 1911 what new model did Rutherford propose for the atom?
In 1911 Rutherford proposed that the positive charge of an atom and most of its mass are concentrated in the nucleus at the centre. Negative electrons orbit the nucleus, just like planets orbit the sun. Most of an atoms volume is in the space between the nucleus and the orbiting electrons. * The overall positive and negative charges must balance. *this was the nuclear atom.
In what year did Ernest Rutherford propose the nuclear atom?
In 1911 Ernest Rutherford proposed the nuclear atom.
Who, in 1913, said that electrons can only follow certain paths otherwise they would spiral into the nucleus?
In 1913 Neils Bohr said that electrons can only follow certain paths otherwise they would spiral into the nucleus.
In what year did Neils Bohr suggest that electrons must follow certain paths otherwise they would spiral into the nucleus?
In 1913 Neils Bohr said that electrons can only follow certain paths otherwise they would spiral into the nucleus.
What model of atom had Neils Bohr proposed by suggesting that electrons must follow certain paths so that they do not spiral into the nucleus?
Neils Bohr had proposed the planetary atom by suggesting that electrons must follow certain paths so that they do not spiral into the nucleus.
In what year was the proton discovered?
In 1918 Rutherford discovered the proton.
Who discovered the proton in 1918?
Rutherford discovered the proton in 1918.
What did Rutherford discover in 1918?
Rutherford discovered the proton in 1918.
Who suggested in 1923 that particles could have both the properties of a wave and a particle?
In 1923 Louis de Broglie suggested that particles could have both the properties of a wave and a particle.
In what year did Louis de Broglie suggested that particles could behave as both a wave and a particle?
In 1923 Louis de Broglie suggested that particles could behave as both a wave and a particle.
In what year did Erwin Schrodinger suggest that an electron has wave properties in an atom and proposed atomic orbitals?
In 1926 Erwin Schrodinger suggested that an electron had wave properties in an atom and proposed atomic orbitals.
Who in 1926 suggested that an electron has wave properties in an atom and proposed atomic orbitals?
Erwin Schrodinger in 1926 suggested that an electron has wave properties in an atom and proposed atomic orbitals.
Who in 1932 discovered the neutron?
James Chadwick discovered the neutron in 1932.
In what year was the neutron discovered by James Chadwick?
The neutron was discovered in 1932 by James Chadwick.
What was discovered in 1932 by James Chadwick?
The neutron was discovered in 1932 by James Chadwick.
TRUE or FALSE Protons and neutrons are of differing masses.
FALSE! Protons and neutrons are of virtually the same mass.
Define an isotope.
Isotopes are atoms of the same element with different numbers of neutrons.
Define the atomic number.
The atomic (proton) number is the number of protons in the nucleus of an atom.
Define the mass number.
The mass (nucleon) number is the number of particles (protons and neutrons) in the nucleus.
TRUE or FALSE Different isotopes of the same element react in the same way?
TRUE! Different isotopes of the same element react in the same way.
What type of particle is involved in chemical reactions?
Electrons are involved in chemical reactions.
Define an ion.
An ion is a positively or negatively charged atom or (covalently bonded) group of atoms (molecular ion).
What unit are the masses of atoms measured using?
Atomic masses are measured using a unit called the unified atomic mass unit, u.
Define the relative isotopic mass.
The relative isotopic mass is the mass of an atom of an isotope compared with one-twelfth of the mass of an atom of carbon-12.
Define the relative atomic mass.
The relative atomic mass, Ar, is the weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon-12.
Define the relative molecular mass.
The relative molecular mass, Mr, is the weighted mean mass of a molecule compared with one-twelfth of the mass of an atom of carbon-12.
Define the relative formula mass.
The relative formula mass in the weighted mean mass of a formula unit compared with one-twelfth of the mass of an atom of carbon-12.
Define the amount of substance.
The amount of substance is the quantity whose unit is the mole. Chemists use ‘amount of substance’ as a means of counting atoms.
What is the unit of the amount of substance?
Mol is the unit of the amount of substance.
What is the Avogadro constant?
The Avogadro constant, NA s the number of atoms per mole of the carbon-12 isotope.
