Chemistry grade 10 - PERIODIC TABLE

In the modern periodic table, elements are arranged according to

• decreasing atomic mass.

• Mendeleev’s original model.

• increasing atomic number.

• when they were discovered.

Group the halogens, are the most reactive of the nonmetal elements because they

• require only one electron to fill their outer energy level.

• have the highest ionization energies.

• have the largest atomic radii.

• are the farthest to the right in the periodic table.

Which of the following is not a main-group element?

• neon.

• oxygen.

• bromine.

• copper.

All elements in Group 2

• are also members of Period 2 in the periodic table.

• are known as the alkaline-earth metals.

• have the same atomic mass.

• have a stable electron configuration.

Which of the following represents an electron configuration for a calcium atom, whose atomic number is 20?

• 1s²2s²2p⁶3s¹3p⁶4s²3d¹.

• 1s²2s²2p⁶3s²3p⁶4s².

• 1s²2s²2p⁶3s¹3p⁶4s³.

• 1s²2s²2p⁶3s²3p⁶4s²3d¹.

Isotopes of an element differ in their

• atomic numbers.

• electron configurations

• numbers of protons.

• numbers of neutrons.

The number of protons of an atom equals

• the number of neutrons.

• the mass number.

• the number of electrons.

• the number of isotopes.

Which of the following has a negative charge?

• Electron.

• Proton.

• Atom.

• Neutron.

How many neutrons are present in an atom of tin that has an atomic number of 50 and a mass number of 119?

• 50.

• 119.

• 69.

• 169.

An atom of an element contains 12 electrons, 12 protons and 12 neutrons. In which group of the periodic table is this element placed?

• Group IVA.

• Group IIIA.

• Group VA.

• Group IIA.