The atom and chemical substances 7th grade

Based on Dalton’s atomic theory, indicate if the sentences are true (T) or false (F): A compound is a composition of various simple substances.

• True

• False

Based on Dalton’s atomic theory, indicate if the sentences are true (T) or false (F): Matter is discreet.

• True

• False

Indicate whether the following representation correspond to simple substances, compounds or mixtures:

• Simple substances

• Compounds

• Mixture

Indicate whether the following representation correspond to simple substances, compounds or mixtures:

• Simple substances

• Compounds

• Mixture

Based on Dalton’s atomic theory, indicate if the sentences are true (T) or false (F): Electrons are massless particles.

• True

• False

Based on Dalton’s atomic theory, indicate if the sentences are true (T) or false (F): The mass of an electron is very small compared to that of a proton.

• True

• False

Based on Dalton’s atomic theory, indicate if the sentences are true (T) or false (F): Atoms are electrically neutral, as they have got twice the amount of electrons than protons.

• True

• False

Label the blank spaces using the following terms: nucleus, electron, proton, neutron:

• a) Nucleus; b) Electrón; c) Proton; d) Neutron

• a) Nucleus; b) Proton; c) Electron; d) Neutron

• a) Electron; b) Proton; c) Nucleus; d) Neutron

Indicate which atom consists of seven protons, seven electrons and nine neutrons:

• Atomic number, A = 7; mass number, Z = 9.

• Atomic number, Z = 7; mass number, A = 9.

• Atomic number, Z = 7; mass number, A = 16.

• Atomic number, A = 7; mass number, Z = 16.

Indicate which of the following descriptions corresponds to a cation Ca²⁺ (Z = 20):

• It is a calcium atom and has got 22 electrons.

• It is a calcium atom that has gained two electrons.

• It is a calcium atom with 18 electrons.

• It is a calcium atom with 22 protons.