Unit 5 the Atom and Ionic vs Covalent Compounds

Who proposed the "Plum Pudding" model of the atom?

• Niels Bohr

• J.J. Thomson

• Ernest Rutherford

• John Dalton

Which atomic model first introduced the idea of electrons orbiting the nucleus in fixed paths?

• Dalton Model

• Bohr Model

• Quantum Model

• Plum Pudding Model

What does the atomic number of an element represent?

• Number of neutrons

• Number of protons

• Number of electrons in the outer shell

• Atomic mass

Which of the following is a physical property of ionic compounds?

• Low melting point

• Poor electrical conductivity when dissolved in water

• High melting point

• Soft and flexible

Tags

NGSS.MS-PS3-4

Which subatomic particle determines the identity of an element?

• Electron

• Neutron

• Proton

• Nucleus

Which model of the atom describes electrons as existing in probability clouds rather than fixed orbits?

• Bohr Model

• Quantum Model

• Rutherford Model

• Dalton Model

Which of the following best explains why ionic compounds conduct electricity when dissolved in water?

• The ions are free to move

• The molecules are neutral

• The electrons are shared

• The atoms are tightly packed

Tags

NGSS.HS-PS2-4

Given the element with atomic number 8 and atomic mass 16, how many neutrons does it have?

• 8

• 16

• 24

• 4

Which statement best describes the difference between ionic and covalent compounds?

• Ionic compounds share electrons, covalent compounds transfer electrons

• Ionic compounds transfer electrons, covalent compounds share electrons

• Both share electrons

• Both transfer electrons

Which of the following best explains why covalent compounds generally have low melting points?

• They have strong ionic bonds

• They have weak intermolecular forces

• They are metals

• They are always gases

Tags

NGSS.MS-PS3-4