T1 AS LEVEL CHEMISTRY SY25-26

What defines the identity of an element?

• The number of neutrons in the atom.

• The number of protons in the atom.

• The number of electrons in the atom.

• The atomic mass of the element.

What types of bonding are there?

• Ionic, covalent, and metallic bonding.

• Hydrogen, van der Waals, and dipole-dipole bonding.

• Covalent, ionic, and hydrogen bonding.

• Metallic, ionic, and molecular bonding.

Why does ionization energy generally decrease down a group?

• The nuclear charge decreases, making it harder to remove electrons.

• The atomic radius decreases, bringing electrons closer to the nucleus.

• The atomic radius increases, making outer electrons easier to remove.

• The number of protons decreases down the group.

What is the formula for percentage yield?

• % yield = (actual yield / theoretical yield) × 100%

• % yield = (theoretical yield / actual yield) × 100%

• % yield = (actual yield + theoretical yield) × 100%

• % yield = (actual yield - theoretical yield) × 100%

What are the characteristics of covalent compounds?

• Covalent compounds typically have high melting and boiling points, are good conductors of electricity, and exist only as solids.

• Covalent compounds typically have lower melting and boiling points, are poor conductors of electricity, and can exist as gases, liquids, or solids.

• Covalent compounds typically have very high melting points, are excellent conductors of electricity, and exist only as gases.

• Covalent compounds typically have moderate melting and boiling points, are fair conductors of electricity, and can exist only as liquids.

What is the octet rule?

• Atoms tend to gain, lose, or share electrons to achieve a full outer shell of eight electrons.

• Atoms always have eight protons in their nucleus.

• Atoms can only gain electrons, not lose or share them.

• Atoms with fewer than eight electrons are unstable.

What are isotopes?

• Atoms of different elements with the same number of neutrons.

• Atoms of the same element with different numbers of neutrons.

• Atoms that have the same mass but different charges.

• Atoms that are chemically identical but physically different.

What is electronegativity?

• The ability of an atom to lose electrons easily.

• The tendency of an atom to attract electrons in a chemical bond.

• The measure of an atom's size in a molecule.

• The energy required to remove an electron from an atom.

What is the difference between a polar and nonpolar covalent bond?

• A polar covalent bond has equal sharing of electrons, while a nonpolar covalent bond has unequal sharing of electrons.

• A polar covalent bond has unequal sharing of electrons, while a nonpolar covalent bond has equal sharing of electrons.

• Both polar and nonpolar covalent bonds have equal sharing of electrons.

• Polar covalent bonds are stronger than nonpolar covalent bonds.

What is the order of orbital filling?

• 1s → 2s → 2p → 3s → 3p → 4s → 3d

• 1s → 2s → 3s → 2p → 3p → 4s → 3d

• 1s → 2p → 2s → 3s → 3p → 4s → 3d

• 1s → 2s → 2p → 3p → 3s → 4s → 3d