1.2 Flashcards
Q: What were the three key ideas in John Dalton’s atomic theory?
A:
Matter is made of atoms which are tiny particles that cannot be created, destroyed, or divided.
Atoms of the same element are identical, and atoms of different elements are different.
Different atoms combine together to form new substances.
Q: What experiment did J.J. Thomson conduct, and what did he discover?
A:
Thomson conducted a cathode-ray tube experiment and discovered the electron as a negatively charged subatomic particle.
What was J.J. Thomson’s proposed atomic model, and how did it differ from Dalton’s model?
A:
Thomson proposed the plum pudding model, where negative electrons are spread throughout soft globules of positively charged material. This model differed from Dalton’s as it suggested that atoms are divisible
Q: Describe Rutherford’s gold foil experiment and its implications.
A:
Rutherford, along with Geiger and Marsden, shot positively charged particles at a thin sheet of gold foil. Contrary to expectations, some particles were deflected, leading to the proposal of the nuclear model, where most of the atom’s mass is concentrated in a dense, positively charged nucleus.
Q: What major change did Rutherford’s model bring to our understanding of atomic structure?
A:
Rutherford’s model replaced the plum pudding model with the nuclear model, which depicted the atom as mostly empty space with a positively charged nucleus at the center and electrons orbiting around it.
Q: What did Niels Bohr propose in his atomic model?
A:
Bohr proposed that electrons orbit the nucleus in fixed shells or orbitals at set distances. Each orbital has a different energy associated with it, explaining the stability of the atom.
Q: How did Bohr’s model address the stability of the atom?
A:
Bohr’s model explained why electrons do not collapse into the nucleus due to the attraction between opposite charges by suggesting that electrons occupy fixed energy levels or shells around the nucleus.
Q: What important discovery resulted from further investigation into the atomic nucleus?
A:
Further investigation revealed the existence of the proton, a subatomic particle with the same mass and positive charge as the hydrogen nucleus. This discovery contributed to our understanding of atomic structure and the composition of the nucleus.
Q: What are atoms?
A:
Atoms are the smallest particles of matter and are considered the building blocks of all substances.
What are the subatomic particles that make up an atom?
A:
The subatomic particles that make up an atom are protons, neutrons, and electrons
Where are protons and neutrons located within an atom?
A:
Protons and neutrons are located at the center of the atom, forming the nucleus.
Q: What are the orbital paths called where electrons move around the nucleus?
A:
Electrons move around the nucleus in orbital paths called shells or energy levels.
Where is the majority of an atom’s mass located?
A:
The majority of an atom’s mass is contained within the nucleus, where the protons and neutrons are located.
What is the mass of an electron compared to that of a proton or neutron?
A:
The mass of an electron is considered negligible compared to the mass of a proton or neutron.
What is the atomic structure of a carbon atom?
A:
A carbon atom consists of a nucleus containing protons and neutrons, surrounded by electron shells where the electrons move
What is the approximate radius of an atom?
A:
The radius of an atom is about
1×10−10
meters
Q: What are the relative masses and charges of protons, neutrons, and electrons?
A:
Protons and neutrons each have a relative mass of 1.
electrons are approximately 1836 times lighter than protons and neutrons, so their mass is considered negligible in comparison.
Q: What is the atomic number of an atom?
A:
The atomic number (or proton number) is the number of protons in the nucleus of an atom. It is also equal to the number of electrons in the atom.
Q: How is the atomic number represented?
A:
Z.
The symbol for the atomic number is
Z
Q: What does the atomic number determine?
A:
The atomic number determines the position of the element on the Periodic Table. It is unique to each element, so no two elements have the same number of protons.
Q: What is the mass number of an atom?
A:
The mass number (or nucleon number) is the total number of protons and neutrons in the nucleus of an atom.
Q: What are isotopes?
A:
Isotopes are atoms of the same element that contain the same number of protons and electrons but a different number of neutrons
What is an ion?
A:
An ion is an atom or group of atoms that has an electrical charge, either positive or negative
Q: How are positive ions and negative ions formed?
A:
Positive ions (cations) are formed when atoms lose electrons, while negative ions (anions) are formed when atoms gain electrons.
