Structure Of An Atom Flashcards
What did Democritus propose about matter?
“Matter is made of indivisible particles called atoms.”
What is the meaning of the Greek word ‘atomos’?
“Indivisible”
Who first suggested that all matter is made up of atoms?
“Democritus”
When did John Dalton propose his atomic theory?
“1808”
According to Dalton, what is the smallest unit of matter?
“Atom”
Which English school teacher revived the atomic theory in the 19th century?
“John Dalton”
What was the title of John Dalton’s work on atomic theory?
“A New System of Chemical Philosophy”
Atoms combine in ______ whole number ratios.
“small”
True or False: Atoms of the same element have different properties.
“False”
True or False: Atoms can be created or destroyed.
“False”
Dalton’s atomic theory states that atoms are ______.
“indivisible”
Which scientist proposed that atoms are like solid balls?
“John Dalton”
According to Dalton, atoms of a particular element are ______ in size, shape, and mass.
“identical”
Which of the following is NOT a postulate of Dalton’s atomic theory? \nA) Atoms are indivisible \nB) Atoms can be created and destroyed \nC) Atoms of an element are identical \nD) Atoms combine in whole number ratios
“B) Atoms can be created and destroyed”
Fill in the blank: All chemical reactions occur due to the ______ or ______ of atoms.
“combination
Multiple Choice: What did John Dalton compare atoms to? \nA) Clouds \nB) Solid balls \nC) Energy waves \nD) Hollow spheres
“B) Solid balls”
Dalton’s atomic theory suggests that atoms of different elements have ______ properties.
“different”
Atoms of different elements differ in ______. \nA) Mass and properties \nB) Shape only \nC) Number of protons only \nD) Electrons only
“A) Mass and properties”
True or False: Dalton proposed that atoms of one element can change into another element.
“False”
What is the key reason behind chemical reactions according to Dalton?
“Combination or separation of atoms”“What experiment did Rutherford perform in 1911?”
What was the purpose of Rutherford’s experiment?
“To determine the internal structure of the atom”
What type of particles did Rutherford use in his experiment?
“Alpha (α) particles”
What material did Rutherford use for his experiment?
“A thin gold foil”
What was surrounding the gold foil to detect particles?
“A photographic plate or ZnS fluorescent screen”
Which radioactive element was used as a source of α-particles?
“Polonium”
Most of the α-particles passed through the gold foil without deflection. What does this indicate?
“Most of the atom is empty space”
Some α-particles were deflected at small angles. What does this indicate?
“They passed close to the nucleus and were repelled by its positive charge”
A few α-particles bounced back. What does this indicate?
“The presence of a small
Who discovered the atomic nucleus?
“Ernest Rutherford”
What is the central part of the atom called according to Rutherford?
“Nucleus”
What is the charge of the nucleus?
“Positive”
According to Rutherford’s model, electrons revolve around the nucleus like ______.
“Planets around the sun”
The force that keeps electrons revolving around the nucleus is called ______.
“Centripetal force”
True or False: According to Rutherford, the nucleus is very large compared to the atom.
“False”
True or False: The nucleus contains protons and neutrons.
“True”
True or False: The atom is mostly empty space.
“True”
True or False: Rutherford’s model was also called the plum pudding model.
“False”
Which of the following is NOT a conclusion of Rutherford’s experiment? \nA) Atoms have a dense nucleus \nB) Atoms are mostly empty space \nC) Electrons are embedded inside the nucleus \nD) The nucleus is positively charged
“C) Electrons are embedded inside the nucleus”
Rutherford’s experiment led to the discovery of which atomic component?
“Nucleus”
Which statement is true according to Rutherford’s atomic model? \nA) Electrons are stationary inside the atom \nB) Protons are located outside the nucleus \nC) Electrons move around the nucleus \nD) The nucleus has a negative charge
“C) Electrons move around the nucleus”
Fill in the blank: The nucleus is responsible for the ______ and ______ of the atom.
“mass
Why do α-particles get deflected when they pass near the nucleus?
“Because both the nucleus and α-particles are positively charged and repel each other”
Which scientist proposed the planetary model of the atom?
“Ernest Rutherford”
According to Rutherford, atoms are neutral because ______.
“The number of protons equals the number of electrons”
Which of the following correctly describes the size of the nucleus? \nA) It is very large compared to the atom \nB) It is very small compared to the atom \nC) It occupies most of the atomic volume \nD) It contains all the electrons
“B) It is very small compared to the atom”
True or False: Rutherford’s model was later modified because it could not explain the stability of electrons in orbit.
“True”
Rutherford’s model of the atom was similar to the ______.
“Solar system”“What was the major flaw in Rutherford’s atomic model?”
Which theory helped Bohr refine Rutherford’s model?
“Quantum theory of radiation by Max Planck”
What did Rutherford’s model fail to explain about atomic spectra?
“Why atoms emit line spectra instead of continuous spectra”
Why should an electron theoretically spiral into the nucleus according to classical physics?
“Because moving charged particles should lose energy and collapse into the nucleus”
True or False: Rutherford’s model was based on the laws of motion and gravitation.
“True”
True or False: Rutherford’s model correctly explained the line spectrum of hydrogen.
“False”
What did Bohr propose about electron orbits?
“Electrons revolve in fixed circular paths called shells or orbits”
What determines the energy of an electron in Bohr’s model?
“Its distance from the nucleus”
What happens when an electron jumps to a lower energy level?
“It emits energy”
What happens when an electron moves to a higher energy level?
“It absorbs energy”
True or False: In Bohr’s model, electrons can exist between orbits.
“False”
True or False: The farther an electron is from the nucleus, the higher its energy.
“True”
Which scientist’s quantum theory influenced Bohr’s atomic model?
“Max Planck”
What is the formula for energy difference between two levels in Bohr’s model?
“ΔE = E2 - E1 = hν”
What does ‘h’ represent in the energy equation?
“Planck’s constant”
In Bohr’s model, what must the angular momentum (mvr) of an electron be?
“An integral multiple of h/2π”
Bohr used which element as a model for his atomic theory?
“Hydrogen”
True or False: According to Bohr, electrons can continuously lose energy while revolving in an orbit.
“False”
Why do electrons not radiate energy while in fixed orbits?
“Because each orbit has a fixed energy”
Which of the following statements is correct about Bohr’s atomic model? \nA) Electrons move in fixed orbits \nB) Electrons emit energy continuously \nC) Electrons spiral into the nucleus \nD) Energy levels are random
“A) Electrons move in fixed orbits”
Fill in the blank: The energy difference between two energy levels is given by ______.
“ΔE = hν”
Who proposed that electrons exist in fixed energy levels?
“Niels Bohr”
How does an atom emit light according to Bohr?
“When an electron jumps from a higher to a lower energy orbit”
True or False: Bohr’s model explains the stability of atoms.
“True”
What did Bohr introduce to fix Rutherford’s atomic model?
“Quantized energy levels”
Which of the following is NOT a postulate of Bohr’s atomic model? \nA) Electrons exist in fixed energy levels \nB) Electrons continuously lose energy \nC) Energy is absorbed or emitted in fixed amounts \nD) Electrons cannot exist between orbits
“B) Electrons continuously lose energy”
According to Bohr, what is the relationship between energy and distance from the nucleus?
“Energy increases with distance from the nucleus”
True or False: The Bohr model applies best to hydrogen atoms.
“True”“What is another name for the orbits in Bohr’s atomic model?”
Which alphabet represents the first shell in Bohr’s model?
“K”
What is the relationship between an electron’s energy and its distance from the nucleus?
“The farther the electron
Which shell has the least energy?
“K-shell (n=1)”
Which shell is the second energy level?
“L-shell (n=2)”
True or False: The nucleus is located at the center of the atom.
“True”
What is the value of Planck’s constant (h)?
“6.6262 × 10⁻³⁴ J·s”
Which fundamental particle is negatively charged?
“Electron”
Which fundamental particle is positively charged?
“Proton”
Which fundamental particle has no charge?
“Neutron”
True or False: Neutrons are found inside the nucleus.
“True”
True or False: Electrons are found inside the nucleus.
“False”
What is the charge of an electron?
“-1.6022 × 10⁻¹⁹ coulombs”
What is the charge of a proton?
“+1.6022 × 10⁻¹⁹ coulombs”
Which subatomic particle has the smallest mass?
“Electron”
What is the mass of an electron in atomic mass units (a.m.u.)?
“0.000548597 a.m.u.”
How many times heavier is a proton compared to an electron?
“1837 times”
How many times heavier is a neutron compared to an electron?
“1842 times”
What is the mass of a proton in atomic mass units (a.m.u.)?
“1.0072766 a.m.u.”
What is the mass of a neutron in atomic mass units (a.m.u.)?
“1.0086654 a.m.u.”
True or False: Protons and neutrons are found in the nucleus.
“True”
True or False: The number of protons determines the atomic number of an element.
“True”
What is the unit of charge for electrons and protons?
“Coulombs”
Which of the following statements is true? \nA) Electrons have a positive charge \nB) Neutrons are lighter than electrons \nC) Protons and neutrons have almost the same mass \nD) The nucleus contains electrons
“C) Protons and neutrons have almost the same mass”
Where are protons located in an atom?
“Inside the nucleus”
Where are neutrons located in an atom?
“Inside the nucleus”
Where are electrons located in an atom?
“Revolving around the nucleus in energy levels”
Fill in the blank: The nucleus contains ______ and ______.
“Protons
Fill in the blank: Electrons revolve around the nucleus in fixed ______.
“Orbits or shells”
Which of the following is NOT a fundamental particle of an atom? \nA) Proton \nB) Neutron \nC) Electron \nD) Photon
“D) Photon”
Which of the following is true about the nucleus? \nA) It is negatively charged \nB) It contains electrons \nC) It contains protons and neutrons \nD) It has no mass
“C) It contains protons and neutrons”
Which scientist proposed that electrons exist in fixed energy levels?
“Niels Bohr”
True or False: The mass of a neutron is slightly more than the mass of a proton.
“True”
What does ‘n’ represent in Bohr’s model?
“The number of the shell (energy level)”
True or False: The farther an electron is from the nucleus, the lower its energy.
“False”
Who discovered the neutron?
“James Chadwick”
What is the primary difference between a proton and a neutron?
“Proton has a positive charge
How does the energy of an electron change as it moves to a higher energy level?
“It increases”
How does an electron release energy?
“By moving to a lower energy level”
True or False: Energy levels in an atom are continuous and electrons can exist between them.
“False”
According to Bohr, what must happen for an electron to move to a higher energy level?
“It must absorb energy”
Which of the following is NOT a characteristic of neutrons? \nA) Neutral charge \nB) Located in the nucleus \nC) Lighter than protons \nD) Mass slightly greater than protons
“C) Lighter than protons”“What is electronic configuration?”
What formula is used to determine the maximum number of electrons in a shell?
“2n²”
How many electrons can the first shell (K-shell) hold?
“2”
How many electrons can the second shell (L-shell) hold?
“8”
How many electrons can the third shell (M-shell) hold?
“18”
How many electrons can the fourth shell (N-shell) hold?
“32”
Which letter represents the first shell in Bohr’s atomic model?
“K”
What is the charge of an electron?
“-1.6022 × 10⁻¹⁹ coulombs”
What is the charge of a proton?
“+1.6022 × 10⁻¹⁹ coulombs”
Which subatomic particle has no charge?
“Neutron”
True or False: Electrons revolve around the nucleus in fixed energy levels.
“True”
True or False: The energy of an electron decreases as it moves away from the nucleus.
“False”
Which scientist proposed that electrons exist in fixed energy levels?
“Niels Bohr”
What is the relative mass of an electron?
“0.00054859 a.m.u.”
What is the relative mass of a proton?
“1.0072766 a.m.u.”
What is the relative mass of a neutron?
“1.0086654 a.m.u.”
What are the four types of sub-shells?
”s
Which sub-shell has only one orbital?
”s sub-shell”
Which sub-shell has three orbitals?
“p sub-shell”
Which sub-shell has five orbitals?
“d sub-shell”
Which sub-shell has seven orbitals?
“f sub-shell”
True or False: Each shell contains only one sub-shell.
“False”
How many orbitals does the p sub-shell have?
“3”
How many orbitals does the d sub-shell have?
“5”
How many orbitals does the f sub-shell have?
“7”
What does ‘n’ represent in electronic configuration?
“The principal quantum number (shell number)”
True or False: The first shell (K-shell) contains only an s sub-shell.
“True”
True or False: The second shell (L-shell) contains s and p sub-shells.
“True”
Which sub-shells are present in the third shell (M-shell)?
”s
Which sub-shells are present in the fourth shell (N-shell)?
”s
What does ‘s’ stand for in sub-shell notation?
“Sharp”
What does ‘p’ stand for in sub-shell notation?
“Principal”
What does ‘d’ stand for in sub-shell notation?
“Diffused”
What does ‘f’ stand for in sub-shell notation?
“Fundamental”
What happens to electron energy as ‘n’ increases?
“It increases”
What is the shape of the s sub-shell?
“Spherical”
What is the shape of the p sub-shell?
“Dumbbell-shaped”
What is the shape of the d sub-shell?
“Complex”
True or False: Electrons can exist between two energy levels.
“False”
True or False: The energy levels are continuous.
“False”
What is the maximum number of electrons in the f sub-shell?
“14”
What happens when an electron moves from a higher to a lower energy level?
“It emits energy”
What happens when an electron moves from a lower to a higher energy level?
“It absorbs energy”
What is another name for sub-shells?
“Sub-energy levels”
Fill in the blank: The first shell (K) has ___ sub-shell.
“One (s)”
Fill in the blank: The second shell (L) has ___ sub-shells.
“Two (s
Fill in the blank: The third shell (M) has ___ sub-shells.
“Three (s
Fill in the blank: The fourth shell (N) has ___ sub-shells.
“Four (s
Which of the following sub-shells can hold a maximum of 10 electrons? \nA) s \nB) p \nC) d \nD) f
“C) d”
Which of the following sub-shells can hold a maximum of 6 electrons? \nA) s \nB) p \nC) d \nD) f
“B) p”
Which of the following sub-shells can hold a maximum of 2 electrons? \nA) s \nB) p \nC) d \nD) f
“A) s”
Which of the following sub-shells can hold a maximum of 14 electrons? \nA) s \nB) p \nC) d \nD) f
“D) f”
True or False: The f sub-shell is present in the second shell.
“False”
Which orbit has the lowest energy?
“First orbit (K-shell)”
What determines the maximum number of electrons in an orbit?
“The 2n² rule”“What is the Aufbau principle?”
What is the increasing order of sub-shell energy levels?
“1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p < 7s…”
How many electrons can an s sub-shell hold?
“2”
How many electrons can a p sub-shell hold?
“6”
How many electrons can a d sub-shell hold?
“10”
How many electrons can an f sub-shell hold?
“14”
What is the maximum number of electrons in the K-shell (n=1)?
“2”
What is the maximum number of electrons in the L-shell (n=2)?
“8”
What is the maximum number of electrons in the M-shell (n=3)?
“18”
What is the maximum number of electrons in the N-shell (n=4)?
“32”
True or False: The 4s sub-shell is filled before the 3d sub-shell.
“True”
Which principle explains the order in which electrons occupy orbitals?
“Aufbau Principle”
Which element has the electronic configuration 1s¹?
“Hydrogen (H)”
Which element has the electronic configuration 1s²?
“Helium (He)”
Which element has the electronic configuration 1s² 2s¹?
“Lithium (Li)”
Which element has the electronic configuration 1s² 2s²?
“Beryllium (Be)”
Which element has the electronic configuration 1s² 2s² 2p¹?
“Boron (B)”
Which element has the electronic configuration 1s² 2s² 2p²?
“Carbon (C)”
Which element has the electronic configuration 1s² 2s² 2p³?
“Nitrogen (N)”
Which element has the electronic configuration 1s² 2s² 2p⁴?
“Oxygen (O)”
Which element has the electronic configuration 1s² 2s² 2p⁵?
“Fluorine (F)”
Which element has the electronic configuration 1s² 2s² 2p⁶?
“Neon (Ne)”
Which element has the electronic configuration 1s² 2s² 2p⁶ 3s¹?
“Sodium (Na)”
Which element has the electronic configuration 1s² 2s² 2p⁶ 3s²?
“Magnesium (Mg)”
Which element has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p¹?
“Aluminum (Al)”
Which element has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p²?
“Silicon (Si)”
Which element has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p³?
“Phosphorus (P)”
Which element has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p⁴?
“Sulfur (S)”
Which element has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p⁵?
“Chlorine (Cl)”
Which element has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p⁶?
“Argon (Ar)”
True or False: 3d orbitals are filled before 4s orbitals.
“False”
True or False: The electronic configuration of an atom determines its chemical properties.
“True”
Fill in the blank: The first shell (K) contains only the __ sub-shell.
”s”
Fill in the blank: The second shell (L) contains __ sub-shells.
”s and p”
Fill in the blank: The third shell (M) contains __ sub-shells.
”s
Fill in the blank: The fourth shell (N) contains __ sub-shells.
”s
Which principle states that no two electrons in an atom can have the same four quantum numbers?
“Pauli Exclusion Principle”
What rule states that electrons occupy orbitals singly before pairing?
“Hund’s Rule”
Which rule states that the maximum number of electrons in a shell is 2n²?
“Bohr’s Rule”
Which element has 17 protons and 17 electrons?
“Chlorine (Cl)”
Which element has 18 protons and 18 electrons?
“Argon (Ar)”
True or False: The 2p sub-shell is filled before the 3s sub-shell.
“True”
Which of the following sub-shells has the highest energy? \nA) 4s \nB) 3d \nC) 5p \nD) 4f
“D) 4f”
Which of the following sub-shells is filled first? \nA) 3p \nB) 4s \nC) 3d \nD) 5s
“B) 4s”
Which sub-shell fills after 4s?
“3d”
Which element has a full valence shell with only two electrons?
“Helium (He)”
Which noble gas has 10 electrons?
“Neon (Ne)”
Which noble gas has 18 electrons?
“Argon (Ar)”“What is the electronic configuration of Sodium (Na)?”
Potassium has the electronic arrangement 2,8,8,1. What is its proton number?
“19”
Write the electronic configuration of Nitrogen (N).
“1s² 2s² 2p³”
Write the electronic configuration of Phosphorus (P).
“1s² 2s² 2p⁶ 3s² 3p³”
Write the electronic configuration of Argon (Ar).
“1s² 2s² 2p⁶ 3s² 3p⁶”
What are isotopes?
“Atoms of the same element with the same atomic number but different mass numbers due to different numbers of neutrons.”
Do isotopes have the same chemical properties?
“Yes
Do isotopes have the same physical properties?
“No
How many isotopes does Hydrogen have?
“Three: Protium (H)
Which isotope of Hydrogen is the most abundant?
“Protium (H)
How many neutrons does Protium (H) have?
“Zero”
How many neutrons does Deuterium (D) have?
“One”
How many neutrons does Tritium (T) have?
“Two”
True or False: Tritium is a commonly found isotope of Hydrogen.
“False
“Which”What are isotopes?”, “Atoms of the same element with the same atomic number but different mass numbers due to different numbers of neutrons.”
“How many isotopes does Carbon have?”, “Three: Carbon-12
Carbon-13
Which isotope of Carbon is the most abundant?
“Carbon-12 (98.98%)”
How many neutrons does Carbon-12 have?
“Six”
How many neutrons does Carbon-13 have?
“Seven”
How many neutrons does Carbon-14 have?
“Eight”
True or False: All isotopes of Carbon have six protons.
“True”
Which Carbon isotope is used in radioactive dating?
“Carbon-14”
Fill in the blank: Carbon-12 has __ neutrons.
“Six”
How many isotopes does Chlorine have?
“Two: Chlorine-35 and Chlorine-37.”
Which isotope of Chlorine is more abundant?
“Chlorine-35 (75.53%)”
How many neutrons does Chlorine-35 have?
“Eighteen”
How many neutrons does Chlorine-37 have?
“Twenty”
True or False: Both isotopes of Chlorine have 17 protons.
“True”
Fill in the blank: Chlorine-37 has __ neutrons.
“Twenty”“What are isotopes?”
How many isotopes does Uranium have?
“Three: Uranium-234
Which isotope of Uranium is the most abundant?
“Uranium-238 (99.245%)”
How many neutrons does Uranium-234 have?
“142”
How many neutrons does Uranium-235 have?
“143”
How many neutrons does Uranium-238 have?
“146”
True or False: All isotopes of Uranium have 92 protons.
“True”
Which Uranium isotope is used in nuclear reactors?
“Uranium-235”
Fill in the blank: Uranium-234 has __ neutrons.
“142”
Which Uranium isotope is used in carbon dating?
“Uranium-235”
What is the isotopic abundance of Uranium-234?
“0.05%”
What is the isotopic abundance of Uranium-235?
“0.75%”
What is the isotopic abundance of Uranium-238?
“99.245%”
True or False: Isotopes of Uranium are used in chemical and medical research.
“True”
What is carbon dating used for?
“Estimating the age of plant and animal remains by measuring radioactive decay.”
Fill in the blank: Iodine-131 is used to treat __.
“Goiter”
True or False: Deuterium is used as a tracer element in biochemical research.
“True”
What is Iodine-131 used for?
“Treatment of goiter.”
Which isotope is used for brain imaging?
“Iodine-131”
True or False: Isotopes can be used in medical treatments like chemotherapy.
“True”“What is an isotope?”
True or False: Isotopes have the same chemical properties but different physical properties.
“True”
Which isotope is used for cancer treatment?
“Radium-226 and Cobalt-60”
Which isotope is used to identify blood circulation problems?
“Sodium-24”
Fill in the blank: Carbon-14 is used in __.
“Carbon dating”
What is Americium-241 used for?
“Smoke detectors and oil well exploration”
Which isotope is used to measure soil moisture content?
“Californium-252”
True or False: Krypton-85 is used to measure dust and pollutant levels in electrical cloth washers.
“True”
Which isotope is used to trace the path of carbon in photosynthesis?
“Carbon-14”
Fill in the blank: Americium-241 is used in __ detectors.
“Smoke”
Which isotope is used in cancer diagnosis?
“Cobalt-60”
True or False: Isotopes can be used to inspect airplane luggage for hidden explosives.
“True”
What are the subatomic particles of an atom?
“Electrons
Who proposed that matter is composed of small particles called atoms?
“Greeks”
According to Dalton’s theory, what is matter composed of?
“Small indivisible particles called atoms.”
True or False: Most of the space in an atom is empty.
“True”
According to Rutherford’s model, what does the atom consist of?
“A positively charged nucleus with electrons revolving around it.”
Who proposed the theory that electrons revolve around the nucleus in certain fixed circular orbits?
“Bohr”
Fill in the blank: The arrangement of electrons around the nucleus is called the __.
“Electronic configuration”
What is the formula for the maximum number of electrons in a particular shell?
“2n^2”
True or False: Shells or energy levels are named alphabetically as K, L, M, N, and so on.
“True”
What are the names of the sub-shells in energy levels?
”s
True or False: Isotopes are used only in medical research.
“False”
Which sub-shell is designated by ‘p’?
“Principal”
