What occurs when an atom loses an electron?

• The atom's radius decreases and the atom becomes a negative ion.

• The atom's radius decreases and the atom becomes a positive ion.

• The atom's radius increases and the atom becomes a negative ion.

• The atom's radius increases and the atom becomes a positive ion.

Answer explanation

When an atom loses an electron, it has fewer negative charges than positive charges, resulting in a positive ion. Additionally, the loss of an electron leads to a decrease in the atomic radius due to reduced electron-electron repulsion.

Tags

NGSS.HS-PS1-2

As chlorine atom becomes a negative ion, the atom

• gains an electron and its radius increases

• gains an electron and its radius decreases

• loses an electron and its radius increases

• loses an electron and its radius decreases

Answer explanation

As a chlorine atom gains an electron to become a negative ion, the increased electron-electron repulsion causes the radius to increase, making 'gains an electron and its radius increases' the correct choice.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which compound contains both ionic and covalent bonds?

• CaCO₃

• CaCl₂

• MgF₂

• H₂CO₃

Answer explanation

CaCO₃ contains both ionic and covalent bonds. The calcium (Ca) and carbonate (CO₃) ions form ionic bonds, while the carbon and oxygen atoms within the carbonate ion are held together by covalent bonds.

Which sample contains particles in a rigid, fixed, geometric pattern?

• CO₂(aq)

• HCl(g)

• H₂O(l)

• KCl(s)

Answer explanation

KCl(s) contains particles arranged in a rigid, fixed, geometric pattern, characteristic of ionic solids. In contrast, CO₂(aq) and HCl(g) are gases or solutions with more random arrangements, while H₂O(l) has a less structured liquid state.

Which type of bond is formed when electrons are transferred from one atom to another?

• covalent

• ionic

• hydrogen

• metallic

Answer explanation

Ionic bonds form when electrons are transferred from one atom to another, resulting in the formation of charged ions. This contrasts with covalent bonds, where electrons are shared, and other bond types like hydrogen and metallic.

Which formula represents an ionic compound?

• NaCl

• N₂O

• HCl

• H₂O

Answer explanation

NaCl represents an ionic compound, consisting of sodium (Na) and chlorine (Cl) ions. The other options (N₂O, HCl, H₂O) are covalent compounds, as they involve sharing electrons rather than transferring them.

Which compound contains ionic bonds?

• NO

• NO₂

• CaO

• CO₂

Answer explanation

CaO contains ionic bonds because it is formed from calcium (a metal) and oxygen (a non-metal), resulting in the transfer of electrons. In contrast, NO, NO₂, and CO₂ are covalent compounds with shared electrons.

Tags

NGSS.HS-PS1-3

Which statement best describes the substance that results when electrons are transferred from a metal to a nonmetal?

• It contains ionic bonds and has a low melting point.

• It contains ionic bonds and has a high melting point.

• It contains covalent bonds and has a low melting point.

• It contains covalent bonds and has a high melting point.

Answer explanation

When electrons are transferred from a metal to a nonmetal, ionic bonds form due to the electrostatic attraction between oppositely charged ions. This results in a substance with a high melting point.

Tags

NGSS.HS-PS1-3

A neutral atom with the electron configuration 2-6 would most likely form a bond with an atom having the configuration

• 2

• 2-2

• 2-8

• 2-8-8

Answer explanation

The atom with configuration 2-6 needs 2 electrons to complete its outer shell. An atom with configuration 2-8-8 has a full outer shell and can provide the needed electrons, making it the most likely candidate for bonding.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which formula is described correctly?

• BaCl2 is covalent and molecular.

• H2O2 is covalent and empirical.

• H3O is ionic and molecular.

• NaCl is ionic and empirical.

Answer explanation

NaCl is correctly identified as ionic due to the transfer of electrons between sodium and chlorine. It is also empirical because its simplest ratio of ions is represented by the formula NaCl.

Tags

NGSS.HS-PS1-1