In a neutral atom: the number of protons is equal to the atomic number (Z). The number of electrons is also equal to the atomic number (Z). The number of neutrons is calculated by subtracting the atomic number from the mass number (A - Z).
More Questions on Journey Inside the Atom
1Given two atoms: Atom A has 17 protons, 18 neutrons, and 17 electrons. Atom B has 18 protons, 18 neutrons, and 18 electrons. Which statement is correct?
→ 2An element has a full outermost electron shell. What can be inferred about its chemical reactivity?
→ 3Describe the main limitation of the Bohr model of the atom.
→ 4An element 'X' has 12 electrons. Which of the following elements would it likely form a stable compound with?
→ 5Which experiment demonstrated that atoms contain negatively charged particles called electrons?
→ 6Explain how the existence of isotopes contradicts one of the main postulates of Dalton's atomic theory.
→ 7Consider a neutral atom with an atomic number of 20. If it forms an ion, what would be the most likely charge on this ion?
→ 8Which of the following statements about the arrangement of electrons in shells is consistent with the Bohr-Bury rules?
→ 9Why are some atoms of the same element found to have different mass numbers?
→ 10An element has an electronic configuration of 2, 8, 8, 1. What is its valency, and what type of ion would it form?
→ 11Explain the concept of an electron shell or energy level in the context of atomic structure.
→ 12Which of the following subatomic particles has a mass approximately equal to that of a proton but carries no electrical charge?
→ 13An ion of element Z has a mass number of 32, 16 protons, and a charge of -2. How many neutrons and electrons does this ion have?
→ 14Why was the 'plum pudding' model unable to explain the results of the alpha-particle scattering experiment?
→ 15An atom X has an atomic number of 9 and an atom Y has an atomic number of 11. Describe the type of bond they would most likely form with each other.
→ 16What is the maximum number of electrons that can be held in the outermost shell of an atom, according to the Bohr-Bury scheme, and what is this rule called?
→ 17If an atom has 19 electrons, 19 protons, and 20 neutrons, what is its symbol with mass number and atomic number?
→ 18An element P has 11 electrons and belongs to the 3rd period. What is its valency, and what type of compound would it most likely form with oxygen?
→ 19Which of the following correctly describes the particles found in the nucleus of an atom?
→ 20Explain how the concept of valency helps in writing the chemical formula of ionic compounds.
→ 21Consider a hypothetical atom with 12 protons and 12 neutrons. If this atom undergoes a chemical reaction where it becomes an ion with a -2 charge, how many electrons does this ion possess?
→ 22Why is the Bohr model still used as a simplified representation for teaching atomic structure, despite its limitations?
→ 23An element has 5 electrons in its outermost shell and belongs to the 3rd period. What is its atomic number?
→ 24What was the significance of the "empty space" concept in Rutherford's model of the atom, compared to Thomson's model?
→ 25An element has 13 protons, 14 neutrons, and 10 electrons. What is its atomic number, mass number, and net charge?
→ 26Why are electrons considered to have negligible mass compared to protons and neutrons, even though they are fundamental particles?
→ 27If an element forms an ion with a charge of +2 and has 18 electrons, what is its atomic number?
→ 28What is the maximum number of electrons that can be accommodated in the N-shell (fourth shell) of an atom?
→ 29Describe the main difference in how electrons are depicted in Rutherford's model versus Bohr's model.
→ 30If a neutral atom has 15 protons and its mass number is 31, how many energy shells are occupied by electrons, and how many electrons are in the outermost shell?
→ 31Which of the following pairs are isotopes?
→ 32What role do neutrons play in the stability of atomic nuclei, particularly for heavier elements?
→ 33An element has an atomic number of 16. What will be its electronic configuration, valency, and type of ion formed?
→ 34Explain the primary difference between the atomic number (Z) and the mass number (A) of an atom.
→ 35An atom of element Y has 17 protons and 20 neutrons. What is its mass number and atomic number?
→ 36How do you determine the group and period of an element based on its electronic configuration, assuming it's a main group element?
→ 37If an atom of an element has 19 electrons, what is the maximum number of electrons that can be accommodated in its third shell (M-shell)?
→ 38An atom has an electron configuration of 2, 8, 8. What is its atomic number, and is it likely to be reactive or unreactive?
→ 39Which of the following statements about the Bohr model of the atom is incorrect?
→ 40Describe the main difference between a cation and an anion, including how each is formed.
→ 41Consider an element X that forms an oxide with the formula X2O3. What is the probable electronic configuration of X if it is in the third period?
→ 42Why is the atomic number a more fundamental property for defining an element than the mass number?
→ 43Given a sample of natural neon, which consists of three isotopes: Ne-20 (90.92%), Ne-21 (0.26%), and Ne-22 (8.82%). Explain why the atomic mass of neon is approximately 20.18 amu, and not a whole number.
→ 44An element has electronic configuration 2, 8, 4. What is its group number and period number in the periodic table?
→ 45Why are canal rays deflected towards the negative plate in an electric field?
→ 46An ion has 18 electrons and 17 protons. What is its symbol and charge?
→ 47Contrast the main features of Thomson's atomic model with Rutherford's atomic model.
→ 48An atom has an atomic number 17 and a mass number 35. It forms a compound with hydrogen, with the formula HX. What is the valency of X in this compound?
→ 49How did the limitations of Rutherford's model regarding atomic stability pave the way for Bohr's postulations about electron orbits?
→ 50Explain the concept of valency in terms of an atom's electron configuration.
→ 51Calculate the number of protons, neutrons, and electrons in an iodide ion (I-) with a mass number of 127. The atomic number of iodine (I) is 53.
→ 52Which of the following elements would be expected to be chemically unreactive?
→ 53What experimental evidence led to the conclusion that the nucleus of an atom is positively charged?
→ 54An element has 2 valence electrons and belongs to the 4th period. Write its full electronic configuration.
→ 55Why did Rutherford's model propose that the nucleus is very small and dense compared to the overall size of the atom?
→ 56Describe one major point of agreement and one major point of disagreement between Dalton's atomic theory and modern atomic theory.
→ 57An atom has 10 protons, 10 neutrons, and 10 electrons. If it loses 2 electrons, what will be its net charge, atomic number, and mass number?
→ 58Which subatomic particle was discovered by J.J. Thomson?
→ 59Consider the elements Magnesium (Mg, Z=12) and Calcium (Ca, Z=20). Both are in Group 2 of the periodic table. How do their electron configurations explain their similar chemical properties?
→ 60Explain why the first shell (K-shell) can hold a maximum of 2 electrons, while the second shell (L-shell) can hold up to 8 electrons, according to the Bohr-Bury rules.
→ 61Which experiment provided the first evidence for the existence of a positively charged nucleus within an atom?
→ 62An element has an atomic number 13. How many electrons are present in its M-shell (third shell) and what is its valency?
→ 63Why are atoms generally considered to be electrically neutral, despite containing charged subatomic particles?
→ 64Which of the following describes the key difference between isotopes and isobars?
→ 65What was the primary limitation of Thomson's 'plum pudding' model regarding the distribution of positive charge within the atom?
→ 66An element M forms a chloride with the formula MCl2. What is the valency of element M, and what type of ion would it typically form?
→ 67Explain why cathode rays are deflected towards the positive plate in an electric field.
→ 68Two elements, A and B, have mass numbers 40 and 39 respectively. Element A has 20 protons, while element B has 19 protons. What is the relationship between elements A and B?
→ 69Explain why the atomic mass of most elements is not a whole number.
→ 70If an atom has 15 protons and a mass number of 31, how many electrons and neutrons does a neutral atom of this element possess?
→ 71A neutral atom of an element has an electronic configuration of 2, 8, 7. What is its valency and what type of ion is it likely to form?
→ 72Describe the key limitation of Rutherford's atomic model that led to the development of Bohr's model.
→ 73An element has an atomic number of 11. Which of the following is true regarding its ion formation and reactivity?
→ 74Which of the following statements about J.J. Thomson's model of the atom is incorrect?
→ 75Why was the discovery of the neutron by James Chadwick crucial for developing a more complete model of the atom, even after protons and electrons were identified?
→ 76Consider two isotopes of carbon: Carbon-12 and Carbon-14. How do these two isotopes differ in terms of subatomic particles, and what is the implication of this difference for their chemical properties?
→ 77An element X has a valency of 3. What would be the most probable electronic configuration for an atom of this element if it is in the third period?
→ 78Rutherford's alpha-particle scattering experiment led to the rejection of Thomson's model. Explain two significant observations from Rutherford's experiment that contradicted Thomson's 'plum pudding' model.
→ 79Consider an atom with 17 protons, 18 neutrons, and 17 electrons. Which of the following statements accurately describes its atomic characteristics?
→ 80Write the complete symbol for the atom with the given atomic number [Z] & mass number [A].
→ 81How are the isotopes of hydrogen represented?
→ 82An atom contains 3 protons, 3 electrons and 4 neutrons. What is its atomic number, mass number & valency?
→ 83Why does Helium have zero valency?
→ 84From the symbol ³²₁₆S, state: i) Atomic number of sulphur ii) Mass number of sulphur iii) Electronic configuration of sulphur
→ 85Give the symbol, relative charge & mass of the three subatomic particles.
→ 86State the maximum capacity of various shells to accommodate electrons.
→ 87How many electrons are present in the valence shell of nitrogen & argon?
→ 88Which kind of elements have tendency to lose electrons? Give example.
→ 89What are valence electrons? Give example.
→ 90Give one achievement and one limitation of J.J. Thomson's model of atom.
→ 91Identify the isotopes out of A, B, C & D: ³³A₁₇, ⁴⁰B₂₀, ³⁷C₁₇, ³⁹D₁₉
→ 92Write the charges on subatomic particles.
→ 93Define the following terms: a) Atomic number b) Mass number
→ 94Name the particles which determine the mass of an atom.
→ 95What are isobars?
→ 96Give the number of protons in ³⁵Cl₁₇.
→ 97What type of charge is present on the nucleus of an atom?
→ 98How many electrons at the maximum can be present in the first shell?
→ 99What was the model of an atom proposed by Thomson?
→ 100How many times is a proton heavier than an electron?
→ 101Which is heavier, neutron or proton?
→ 102Name the scientist and his experiment which proved that the nucleus of an atom is positively charged.
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