Chemistry 1 Extended Notes

HIGHER SECONDARY CERTIFICATE 2028 Science Group • English Version • Dhaka Education Board Chemistry First Paper Subject Code 176 Complete Chapter Notes Full syllabus • Labelled diagrams • Board style questions Prepared by Md Ahbab Hamid Khan ahbab.dev September 6, 2026

HSC 2028 • Chemistry First Paper • Code 176 1 Contents How this paper is marked 4 1 Safe Use of Laboratory 5 1.1 What this chapter is about . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Syllabus map for this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3 Hazard classes and hazard symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4 Safety rules, protective wear and storage . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.5 Fire in the laboratory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.6 First aid you must be able to write . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.7 Waste, storage and safe practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.8 Apparatus and the correct way to use it . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.9 The chemical balance and correct weighing . . . . . . . . . . . . . . . . . . . . . . . 9 1.10 The mole and the Avogadro number . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.11 Concentration of a solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.12 Standard solution,

HSC 2028 • Chemistry First Paper • Code 176 2 3 Periodic Properties of Elements and Chemical Bonding 34 3.1 What this chapter is about . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3.2 Syllabus map for this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3.3 The modern periodic table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3.4 Effective nuclear charge and shielding . . . . . . . . . . . . . . . . . . . . . . . . . . 36 3.5 Atomic radius and ionic radius . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 3.6 Ionisation energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.7 Electron affinity and electronegativity . . . . . . . . . . . . . . . . . . . . . . . . . . 38 3.8 The transition elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 3.9 Why atoms form bonds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.10 The ionic bond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.11 The covalent bond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 3.12 The