BS Nursing Entry Test Chemistry Syllabus

What is ionization energy?

The minimum energy required to remove the most loosely bound (outermost) electron from a gaseous atom.

How does electronegativity change across a period and down a group?

Electronegativity increases across a period and decreases down a group. Fluorine is the most electronegative element.

How does metallic character change across a period and down a group?

Metallic character decreases across a period and increases down a group.

What do the period number and group number tell you about an element's electrons?

The period number equals the number of electron shells; the group number (for main-group elements) equals the number of valence electrons.

Name the families of Group 1, Group 2, Group 17, and Group 18.

Group 1 = Alkali metals, Group 2 = Alkaline earth metals, Group 17 = Halogens, Group 18 = Noble gases.

Why are noble gases (Group 18) chemically unreactive?

They have a complete, stable outermost electron shell (octet, or duplet for He), so they have little tendency to gain, lose, or share electrons.

What is ionic (electrovalent) bonding?

A bond formed by the complete transfer of electrons from a metal to a non-metal, producing oppositely charged ions held together by electrostatic attraction.

Give a typical example of an ionic compound and the ions formed.

Sodium chloride (NaCl): Na loses one electron to form Na⁺, and Cl gains one electron to form Cl⁻.

List two characteristic properties of ionic compounds.

High melting and boiling points; conduct electricity when molten or dissolved in water (not when solid).

What is covalent bonding?

A bond formed by the mutual sharing of electron pairs between two non-metal atoms.

Distinguish between a single, double, and triple covalent bond.

Single bond = 1 shared pair (2 electrons), double = 2 shared pairs (4 electrons), triple = 3 shared pairs (6 electrons).

What is the difference between polar and non-polar covalent bonds?

Polar covalent bonds form between atoms of different electronegativities (unequal sharing); non-polar covalent bonds form between atoms of equal/similar electronegativity (equal sharing).

What is a coordinate (dative) covalent bond?

A covalent bond in which both shared electrons are donated by a single atom (e.g., NH₄⁺, H₃O⁺).

What is hydrogen bonding?

A relatively strong intermolecular attraction between a hydrogen atom bonded to a highly electronegative atom (N, O, or F) and a lone pair on another electronegative atom.

Why does water have an unusually high boiling point compared to other Group 16 hydrides?

Because of extensive hydrogen bonding between water molecules, which requires extra energy to break.

What does VSEPR theory predict?

The shape (geometry) of a molecule based on the repulsion between electron pairs around the central atom, which arrange themselves as far apart as possible.

What are the shapes and bond angles of CH₄ (methane) and H₂O (water)?

CH₄ is tetrahedral (109.5°). H₂O is bent/angular (about 104.5°) due to two lone pairs.

What are the shapes of CO₂ and NH₃?

CO₂ is linear (180°); NH₃ is trigonal pyramidal (about 107°).

State the postulates of the Kinetic Molecular Theory for an ideal gas (any two).

Gas particles are in constant random motion; their volume is negligible compared to container volume; collisions are perfectly elastic; there are no intermolecular forces; average kinetic energy is proportional to absolute temperature.

State Boyle's Law and its equation.

At constant temperature, the volume of a fixed mass of gas is inversely proportional to its pressure. P₁V₁ = P₂V₂.

State Charles's Law and its equation.

At constant pressure, the volume of a fixed mass of gas is directly proportional to its absolute temperature. V₁/T₁ = V₂/T₂.

Write the ideal gas equation and identify each term.

PV = nRT, where P = pressure, V = volume, n = number of moles, R = gas constant, T = absolute temperature (Kelvin).

List two characteristic properties of the liquid state.

Definite volume but no definite shape (takes the shape of its container); particles are close together but can move/slide past one another.

What is evaporation, and how does it differ from boiling?

Evaporation is the change from liquid to vapor occurring only at the surface at any temperature; boiling occurs throughout the liquid at a fixed boiling point when vapor pressure equals atmospheric pressure.

Compare the two types of solids: crystalline vs amorphous.

Crystalline solids have a regular, ordered arrangement of particles and sharp melting points (e.g., NaCl, diamond); amorphous solids have irregular arrangement and no sharp melting point (e.g., glass, plastic).

Define enthalpy change (ΔH) of a reaction.

The heat energy absorbed or released by a reaction at constant pressure. ΔH = H(products) - H(reactants).

State Hess's Law.

The total enthalpy change for a reaction is the same regardless of the route taken, provided the initial and final conditions are the same (energy is conserved/a state function).

Distinguish between exothermic and endothermic reactions by their ΔH sign and energy flow.

Exothermic reactions release heat to the surroundings and have a negative ΔH. Endothermic reactions absorb heat from the surroundings and have a positive ΔH.

What is a reversible reaction, and what is dynamic equilibrium?

A reversible reaction can proceed in both forward and reverse directions. Dynamic equilibrium is reached when the forward and reverse reaction rates are equal, so concentrations remain constant.

State Le Chatelier's Principle and predict the effect of increasing pressure on a gaseous equilibrium.

If a stress (change in concentration, temperature, or pressure) is applied to a system at equilibrium, the equilibrium shifts to counteract that change. Increasing pressure shifts the equilibrium toward the side with fewer gas moles.