This chapter introduces the structure of atoms, focusing on sub-atomic particles, atomic models, and quantum mechanics, which are fundamental to understanding chemistry.
Structure of Atom – Formula & Equation Sheet
Essential formulas and equations from Chemistry Part - I, tailored for Class 11 in Chemistry.
This one-pager compiles key formulas and equations from the Structure of Atom chapter of Chemistry Part - I. Ideal for exam prep, quick reference, and solving time-bound numerical problems accurately.
Key concepts & formulas
Essential formulas, key terms, and important concepts for quick reference and revision.
Formulas
E = hν
E is the energy (in joules) of a photon, h is Planck's constant (6.626 × 10⁻³⁴ J·s), and ν is the frequency (in Hz). This formula relates the energy of a photon to its frequency.
c = νλ
c is the speed of light (≈ 3 × 10⁸ m/s), ν is the frequency, and λ is the wavelength (in meters). This equation shows the relationship between the speed of light, its frequency, and wavelength.
ΔE = E_f - E_i
ΔE is the change in energy during a transition, E_f is the energy of the final state, and E_i is the energy of the initial state. It indicates the energy difference when an electron transitions between energy levels.
E_n = - (2.18 × 10⁻¹⁸ J/n²)
E_n is the energy of the nth orbit in hydrogen, where n is the principal quantum number. This formula quantifies the energy of an electron in a certain orbit.
r_n = n²a₀
r_n is the radius of the nth orbit, n is the principal quantum number, and a₀ is the Bohr radius (52.9 pm). This relation describes how the radius of orbits expands as n increases.
Z_eff = Z - S
Z_eff is the effective nuclear charge experienced by an electron, Z is the atomic number, and S is the shielding constant. This formula helps understand how inner electron shielding affects outer electron attraction.
λ = h/p
λ is the de Broglie wavelength, h is Planck's constant, and p is the momentum of the particle (mass × velocity). This equation shows the wave-like properties of matter.
E = mc²
E is energy, m is mass (in kg), and c is the speed of light (≈ 3 × 10⁸ m/s). This formula expresses the equivalence of mass and energy, foundational to modern physics.
Statistical distribution laws: (Number of orbitals in subshell) = 2l + 1
Where l is the azimuthal quantum number. This equation indicates how many orbitals exist within each subshell based on the shape defined by l.
n = 2, l = 0 (1s orbital)
An example of quantum numbers indicating the basic structure of atomic orbitals, where n is the principal quantum number and l is the azimuthal quantum number, defining the orbital shape.
Equations
ν_0 = W/h
ν_0 is the threshold frequency, W is the work function (energy needed to remove an electron), and h is Planck's constant. This equation defines the frequency required to emit electrons from a material.
K.E. = h(ν - ν_0)
K.E. is the kinetic energy of the emitted electron, and ν is the frequency of the incident light. This equation provides a link between incident light frequency and the energy of ejected electrons.
ΔE = hf
ΔE represents the energy difference between quantized states, h is Planck's constant, and f is the frequency of the emitted or absorbed radiation. This equation is crucial for understanding atomic transitions.
N = n²
N is the total number of orbitals in a principal energy level, representing the filled and unfilled states based on the principal quantum number n. This equation provides a systematic approach to electron configuration.
v = 3.29 × 10^15 (1/n^2)
This equation expresses the relationship of frequencies observed in the hydrogen spectrum transition from energy level n to ground state. It shows how spectral lines can be predicted.
E = - 2.18 × 10⁻¹⁸ Z²/n²
E is the energy of an electron in hydrogen-like atoms, Z is the atomic number, and n is the principal quantum number. This equation helps calculate the energy levels specific to different atomic species.
E = W + K.E.
E represents the total energy of a photon as it interacts with an electron, encompassing the work function (W) and the kinetic energy (K.E.) of the emitted electron after the reaction.
λ = h/mv
Where m is mass and v is velocity. This equation is also known as de Broglie equation, highlighting the wave-particle duality phenomenon, crucial for quantum mechanics understanding.
n = 1, l = 0 (1s), n = 2, l = 1 (2p)
These combinations of quantum numbers help define the electronic structure of atoms, reflecting the arrangement of electrons within orbitals.
Z = P + (-e)
Summarizes that for a neutral atom, the atomic number (Z) is equal to the number of protons (P) minus electrons (with a negative charge). This is a foundational concept for atomic structure.
This chapter introduces basic concepts of chemistry, including the study of matter, its properties, and its transformations. Understanding these concepts is crucial for students as they lay the foundation for further studies in chemistry.
Start chapterThis chapter discusses the system of classifying elements based on their properties and the periodicity observed in these properties. It is vital for understanding chemical behavior and the organization of the periodic table.
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Start chapterThis chapter introduces thermodynamics, the study of energy changes in chemical reactions and processes. Understanding thermodynamics is essential for predicting how and why reactions occur.
Start chapterThis chapter covers the principles of chemical equilibrium, including its significance in biological and environmental processes. It emphasizes understanding dynamic equilibrium, the equilibrium constant, and the factors affecting equilibrium states.
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