Which atomic model is characterized by orbiting electrons around the atom’s nucleus?

• Planetary model

• Nuclear atomic model

• Raisin bread atomic model

• Quantum mechanical model

Who is the scientists that explained that there is only a probability that the electron can be found in a certain volume in space around the nucleus using mathematical calculations?

• Neils Bohr

• Werner Heisenberg 

• Louis de Broglie

• Erwin Schrodinger

Valence electron is the number of electrons in the outermost energy level of an atom. Which of the following pairs of elements and valence electrons is incorrect?

• Al - 3

• Br - 7

• S - 4

• Sr - 2

Electron configuration shows the distribution of electrons in an atom. Which configuration is possible in an excited state of an electron?

• He2: 1s2

• C6: 1s2 2s1 2s3

• Ne10: 1s2 2s2 2p5 3s1

• Na11: 1s2 2s2 2p6 3d1

Which of the following sublevels is correctly designated?

• 2s3 

• 3f9 

• 2p6

• 4d11

Which electron configuration represents a neutral atom of nitrogen with 7           electrons?

• 1s2 2s1 2p4

• 1s2 2s2 2p3

• 1s1 2s1 2p5

• 1s2 2s2 2p4

A neutral atom has an electron configuration of 1s2 2s2 2p6 3s2. Which of the following statements is INCORRECT?

• The atom is in a ground state.

• The atom is in an excited state.

• The atom has 12 electrons.

• 2s and 2p orbitals are filled completely.

Which element has correct electron configuration?

• Ca20 – 1s2 2s2 2p6 3s2 3p6 4s2

• Al 13 – 1s2 2s2 2p4 3s2 3p3

• Mg12 –1s2 2s2 2p8

• K 19 – 1s2 2s2 2p6 3s3 3p6

Which statement about an electron's orientation on its energy level is INCORRECT?

• Orbital is a region where an electron can be found.

• An electron can absorb energy when it jumps to a higher energy level.

• An electron can emit energy when it jumps to a higher energy level.

• Filling an electron in an atom starts from lower energy to highest energy level.

A green color was observed in the flame test of a barium salt. The energy producing this color is emitted when ______.

• electrons in the highest levels are expelled

• electrons drop back to lower energy levels

• oxidation takes place

• electrons are raised to higher energy levels by the heat of the flame