Question

The region of space where there is maximum probability of finding an electron at any instant is (1) an orbit (2) an orbital (3) a stationary state (4) subshell

Short answer

The correct answer is (2) orbital.

Step-by-step solution

- Understanding Terms

Identify the definitions of each term provided in the options. An orbit is a fixed path as defined in the Bohr model. An orbital is a region in an atom where there is a high probability of finding an electron, according to quantum mechanics. A stationary state refers to a stable energy state of the atom. A subshell is a subdivision of electron shells separated by electron orbitals.

- Analyzing the Question

The question asks for the region where there is a maximum probability of finding an electron at any instant. This concept corresponds to the quantum mechanical model of the atom.

- Matching Concepts

Based on the definitions and the concept of probability in the quantum mechanical model, the term that best matches the description is an 'orbital'.

Conclusion

The correct answer is (2) orbital, as it denotes the area where there's the highest probability of finding an electron.

Key concepts

Orbit

In the early 20th century, Niels Bohr introduced the concept of an orbit within the Bohr model of the atom. An orbit is a fixed, circular path around the nucleus where electrons are thought to revolve, much like planets around the sun. These orbits were associated with specific energy levels. However, this model couldn't fully explain the behavior of electrons in more complex atoms. Later, quantum mechanics provided a more accurate understanding. Remember, orbits are about fixed paths and specific energies, but lack the probability aspects crucial in modern atomic theory.

Orbital

An orbital is a fundamental concept in quantum mechanics, which describes a region in an atom where there's a high probability of finding an electron. Unlike an orbit, an orbital doesn't define a fixed path but a cloudy, three-dimensional area around the nucleus. Each orbital can hold up to two electrons with opposite spins. There are different types of orbitals (s, p, d, f) with distinct shapes and orientations. The idea of orbitals helps better explain the behavior and arrangement of electrons in atoms.

Stationary State

A stationary state refers to a stable energy level of an atom where the energy remains constant as long as the system remains undisturbed. This concept is crucial in understanding how electrons occupy discrete energy levels or 'quantum states' without radiating energy. When an electron is in a stationary state, it doesn't lose or gain energy. However, if an electron absorbs or emits a photon, it can transition between these stationary states leading to a different energy level.

Subshell

A subshell is a division of electron shells in an atom, categorized by the type of orbitals it contains (s, p, d, f). Each shell is divided into one or more subshells, and each subshell consists of orbitals. For instance, the second shell (n=2) has two subshells: 2s and 2p. Subshells help in organizing the arrangement of electrons within an atom. The electronic structure is often written using the subshell notation to indicate the distribution of electrons, such as 1s^2 2s^2 2p^6 for the element neon.