Unit 1⚛️ atomic structure and bonding ⚛️

• What are protons and where are they found in an atom?

  Protons are positively charged particles found in the center of an atom.
• What is the charge of electrons?

  Electrons have a negative charge.
• Where are neutrons located in an atom?

  Neutrons are found in the nucleus of an atom.
• What does nuclide notation represent?

  Nuclide notation represents the chemical symbol, atomic number, and mass number of an atom.
• How is the mass number calculated?

  The mass number is calculated by adding the number of protons and neutrons.
• What is the atomic number of chlorine?

  The atomic number of chlorine is 17.
• What are isotopes?

  Isotopes are atoms with the same number of protons but different numbers of neutrons.
• What is the valency of an element?

  The valency of an element depends on the group it is found in the periodic table.
• What is the relationship between valency and the number of bonds an element can make?

  • The valency number directly relates to the number of bonds the element can make.
  • It is determined by the group in the periodic table.
• What happens to atoms during chemical reactions regarding electrons?

  Atoms lose or gain electrons to achieve a stable electron arrangement.
• What is formed when an atom loses electrons?

  An atom that loses electrons becomes a positively charged ion.
• What is formed when an atom gains electrons?

  An atom that gains electrons becomes a negatively charged ion.
• What is the electron arrangement of a sodium atom?

  The electron arrangement of a sodium atom is 2, 8, 1.
• What is the electron arrangement of a sodium ion?

  The electron arrangement of a sodium ion is 2, 8.
• What is the electron arrangement of a chlorine atom?

  The electron arrangement of a chlorine atom is 2, 8, 7.
• What is the electron arrangement of a chloride ion?

  The electron arrangement of a chloride ion is 2, 8, 8.
• What are the characteristics of covalent bonding?

  • A covalent bond is formed by a pair of electrons shared between two atoms.
  • Molecules can be diatomic or consist of multiple atoms.
• What are the types of molecular shapes?

  • Linear molecule
  • Angular molecule
  • Trigonal pyramidal
  • Tetrahedral molecule
• What are the properties of ionic bonding?

  • Ionic bonding involves positively and negatively charged ions.
  • Electrostatic attraction between oppositely charged ions forms ionic bonds.
• How do melting and boiling points relate to bond strength?

  • Stronger forces lead to higher melting and boiling points.
  • Covalent networks have strong covalent bonds.
  • Ionic lattices have strong ionic bonds.
  • Covalent molecules have weak forces of attraction.
• What is the solubility of ionic and covalent compounds?

  • Ionic compounds are more soluble in aqueous solvents.
  • Covalent molecules are more soluble in non-aqueous solvents.
  • Covalent networks are insoluble in any solvent.
• How does electrical conductivity vary among substances?

  • Metals conduct electricity as solids or liquids.
  • Non-metals and covalent substances are electrical insulators.
  • Ionic substances do not conduct as solids but do conduct when molten or in solution.
• What is the relative atomic mass (RAM) of an element?

  The RAM is an average mass of one atom of the element, affected by the relative proportions of isotopes.
• How is the RAM calculated using isotopes?

  The RAM can be calculated using the formula: \frac{(\% \text{abundance of isotope 1} \times \text{mass of isotope 1}) + (\% \text{abundance of isotope 2} \times \text{mass of isotope 2})}{100}
• What is the RAM of chlorine given 75% of $^{35}Cl$ and 25% of $^{37}Cl$?


  The RAM of chlorine is $35.5$.
• What is the electron arrangement limit for the first shell?

  The first shell can hold 2 electrons.
• What is the electron arrangement limit for the second shell?

  The second shell can hold up to 8 electrons.
• What is the electron arrangement limit for the third shell?

  The third shell can hold up to 8 electrons.
• How do electrons fill the shells in an atom?

  Electrons occupy the shell nearest the nucleus before moving to outer shells.
• What is the significance of the valency number in chemical bonding?

  The valency number indicates how many bonds an element can form.
• What happens to the charge of an atom when it gains or loses electrons?

  The atom becomes charged and forms an ion when it gains or loses electrons.
• What does the + sign in $^{23}_{11}Na^+$ indicate?


  The + sign indicates that the sodium ion has an overall positive charge.
• What does the - sign in $^{35}_{17}Cl^−$ indicate?


  The - sign indicates that the chloride ion has an overall negative charge.
• What is the role of the data booklet in determining electron arrangements and charges?

  The data booklet provides information to work out the electron arrangement and charge on an ion.
• What is the term used to describe the join between atoms in elements or compounds?

  Bond
• Between which types of atoms are covalent bonds usually formed?

  Non-metal atoms
• What is a covalent bond?

  A pair of electrons shared by two atoms
• What is a molecule?

  A small group of atoms held together by covalent bonds
• What is the chemical formula for a water molecule?

  H₂O
• What does a chemical formula indicate about a substance?

  It tells which elements it is made from and the number of atoms of each element