Periodic

As you move from left to right across a period, the number of valence electrons

• increase

• stays the same

• increases then decreases

• decreases

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Ionization energy is the energy needed to _________ an electron.

• Fission

• Explode

• Remove

• Add

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which element in Period 3 has the highest melting point?

• Silicon (Si)

• Germanium (Ge)

• Carbon (C)

• Argon (Ar)

The number of protons in one atom of an element is that element’s

• mass number.

• balanced charge

• atomic number

• isotope

To find the number of neutrons in an atom, you would subtract

• mass number from atomic number

• atomic number from mass number

• atomic number from electron number

• isotope number from atomic number

Which statement is true about oxygen-16 and oxygen-18 ?

• They do not have the same number of protons

• their atoms have identical mass

• they are isotopes of oxygen

• they have the same mass number

Which list of elements contains only metals?

• carbon, iodine, tin

• tin, copper, cesium

• helium, iron, copper

• iodine, carbon, argon

Which statement is true about the metalloid silicon?

• Silicon is a better conductor of electric current than silver is.

• Silicon does not conduct electric current under any conditions.

• Silicon's ability to conduct electric current does not vary with temperature.

• Silicon is a better conductor of electric current than sulfur is.

In science lab, your teacher gives you two small pieces of matter and tells you that one piece is a metal and one is a nonmetal. Without changing the size or shape of the pieces, how could you test them to determine which is the metal?

• Test the density

• Test the conductivity

• Test the viscosity

• Test the hardness

The Modern Periodic Table of Elements is arranged by

• atomic mass

• atomic number

• valence electrons

• number of isotopes