Atomic Structure & Bonding for Mechatronic Engineering | Lecture Review

35 Q&A flashcards covering atomic structure, electron configuration, periodic trends, bonding types, material properties, and their relevance to mechatronic engineering.

Why is understanding engineering materials fundamental for mechatronic engineers?

Because it explains why materials behave the way they do, enabling informed design, material selection, and reliable system development.

What are the three primary types of atomic bonding highlighted for material selection in mechatronics?

Metallic, ionic, and covalent bonding.

How does metallic bonding influence the ductility of metals?

The delocalised ‘sea’ of electrons allows metal atoms to slide past one another, giving metals high ductility and malleability.

Why are ceramics generally hard and brittle?

They possess ionic and/or covalent bonds that are strong but highly directional, making dislocation motion difficult and leading to brittleness.

How can heat treatment affect the microstructure of a metal component?

It alters grain size and dislocation density, which changes mechanical properties such as strength and toughness.

Name the two main parts of an atom and give their approximate diameters.

The nucleus (~10⁻¹⁴ m) and the electron cloud (~10⁻¹⁰ m).

State the charge and approximate mass of a proton.

Charge: +1.602 × 10⁻¹⁹ C; Mass: 1.673 × 10⁻²⁴ g.

What is the atomic number of an element?

The number of protons in its nucleus.

Define atomic mass.

The average mass of an element’s atoms, accounting for all isotopes, expressed in atomic mass units (amu).

In the periodic table, what does a group (column) signify?

Elements in the same group have the same number of valence electrons and similar chemical behaviour.

Write the equation that gives the energy of one quantum of electromagnetic radiation.

E = h v, where h is Planck’s constant and v is frequency.

Give the value of Planck’s constant used in the lecture notes.

6.63 × 10⁻³⁴ J·s.

What does electron configuration describe?

The arrangement of electrons in an atom’s shells and subshells.

State the Pauli exclusion principle.

No two electrons in an atom can have the same set of four quantum numbers.

How many electrons can the s, p, d, and f subshells hold, respectively?

s: 2, p: 6, d: 10, f: 14.

What formula gives the maximum number of electrons in a shell?

2n², where n is the principal quantum number.

List the correct filling order of orbitals up to 7p.

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p.

Why are noble gases chemically inert?

Their outermost shells are completely filled (s²p⁶ except He which is 1s²), giving them stable configurations.

What is a cation and how is it formed?

A positively charged ion formed when an atom loses one or more electrons.

On what scale is electronegativity measured, and what are its limits?

From 0 to 4.1, with 4.1 being the most electronegative.

Compare ionic and covalent bonding in terms of electron behaviour.

Ionic: electrons are transferred between atoms forming oppositely charged ions; Covalent: electrons are shared between atoms.

What feature of metallic bonding gives metals high electrical conductivity?

The presence of free, delocalised electrons that move easily through the lattice.

Describe the formation of sodium chloride (NaCl) via ionic bonding.

Na loses one electron to become Na⁺; Cl gains one electron to become Cl⁻; electrostatic attraction between Na⁺ and Cl⁻ forms the ionic bond.

What is the coordination number of Na⁺ in a NaCl crystal?

6 (each Na⁺ is surrounded by 6 Cl⁻ ions).

How does lattice energy generally correlate with melting point?

Higher lattice energy usually corresponds to a higher melting point due to stronger ionic attractions.

What causes electron cloud overlap in covalent bonding?

Atoms share valence electrons, bringing their electron clouds together to form a shared pair.

Which bonding pattern gives benzene its hexagonal ring structure?

Alternating single and double covalent bonds between carbon atoms.

Why are metallic bonds described as non-directional?

Valence electrons are shared among many atoms in all directions, not confined to specific atom–atom lines.

Which metal exhibits stronger metallic bonding, sodium (Na) or calcium (Ca), and why?

Calcium, because it contributes two valence electrons, increasing the electron density and bond strength.

Using 2n², what is the maximum number of electrons in the third shell (n = 3)?

18 electrons.

Give the full ground-state electron configuration of iron (Z = 26).

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶.

Which material property derived from atomic bonding is crucial for choosing gears in mechatronic designs?

Mechanical strength (linked to metallic bonding in steels).

How does knowledge of grain boundaries help in failure analysis of devices?

It allows engineers to predict sites of crack initiation, fatigue, and wear, improving reliability and design.

Why are nanomaterials and MEMS often based on precise crystal structures?

Their unique, size-dependent behaviours arise from atomic-scale interactions and ordered structures.

How do electropositive elements behave during chemical reactions?

They tend to lose electrons to form positively charged cations.