Atomic Theory Flashcards
Dalton, Thomson, and Rutherford
Which scientists first described all matter in terms of atoms and their properties?
Dalton
What did Dalton say all matter is made of?
tiny particles called atoms
What is Lavoisier’s law of conservation of mass?
mass is neither created nor destroyed in chemical reactions.
What is the law of constant composition?
States that elements combine in fixed ratios/proportions to form compounds, and it does not depend upon the source or the method of preparation
Dalton claimed that atoms cannot be…?
created, destroyed, or divided
What theory explains that atoms of the same element are identical in size, mass, and properties?
Dalton’s Atomic Theory
In Dalton’s atomic theory, What does he claim about elements?
They are all different from one another and they contain distinct properties
In Dalton’s atomic theory, what are compounds?
atoms of different elements combined in fixed whole-number ratios
In Dalton’s atomic theory, what are chemical reactions?
Atoms separated, recombined, and rearranged into new substances
What was Dalton’s strength?
Able to explain why elements differ from non- elements and from each other
What was Dalton’s weakness?
Incorrect about how atoms are indestructible and indivisible. Atoms can be split into subatomic particles (protons, neutrons, and electrons)
What is the plum pudding model of atom?
first model to show the inside of an atom
shows how elections are negatively charged particles within the positively charged.
what are electrons in Thomson’s atomic theory?
negatively charge particles that are found in the space surrounding the nucleus
What did Thomson contribute to the atomic theory?
Atoms are divisible and they contain electrons
What is Thomson’s cathode ray?
stream of electrons that are released from the negative electrode (cathode) in a vacuum tube. These rays are invisible but can be detected when they strike certain materials, causing them to glow
How did Thomson use the cathode ray to study particles?
Cathode rays helped in discovering the electron and developing atomic models
What was Thomson’s strength?
discovered the electron and the charges inside an atom
What was Thomson’s weakness?
arrangement of negative and positive changes incorrect
What was Rutherford’s strength?
able to explain the organization of charges in an atom
What was Rutherford’s weakness?
doesn’t clearly explain how the electrons are organized outside of the nucleus (especially if an atom has many electrons)
What is Rutherford’s gold foil experiment?
showed that the atom is mostly empty space with a tiny, dense, positively charged nucleus
What is Rutherford’s atom model called?
the nuclear model of the atom
What did Rutherford find out about atoms?
They have a small, dense, positively charged nucleus where most of the mass is concentrated
Who first made up the idea of matter?What did he propose?
Greek philosopher Democritus proposed the idea that matter is made up of tiny particles that exist in empty space.
What is the kinetic molecular theory of matter?
Based on the idea that matter is made up of tiny particles in motion.
What did Dalton do that Democritus couldn’t
he was able to conduct controlled scientific experiments. Had more access glassware the measure changes in matter.
What are electrons?
negatively charged particles that are found in the space surrounding the nucleus
What are nucleus?
positively charged centre of an atom that contains protons and neutrons; smaller compared to atoms
what are protons?
positively charged particles found in the nucleus of an atom
What are neutrons?
particles with no charge that are found in the nucleus of an atomhnm
If you want to change the charge of the atom, you can
add a proton or electron
if you want to change the type of element the atom is, you can
add a proton
If you want to change the mass of your atom, you can
add a proton or neutron
If you add 1 proton and 1 neutron to an atom will and element and mass change
Yes, adding a proton and neutron can change the atom, mass, or/and unit. The charge would change from the old charge to add 1 position
How many protons and electrons tell between positive or negative ions
Positive: more protons than electrons
Negative: more electrons than protons
create a rule of determining the mass of an atom
add number of proton and number of neutrons
