Atomic Theory and Periodic Table

How many protons are in an atom represented by 220 Ra?

• A. 132

• B. 88

• C. 308

• D. 220

The elements that are characterized by the presence of an incomplete d sublevel are called-

• A. transition elements

• B. lanthanoids

• C. halogens

• D. alkali earth metals

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

The atomic number corresponds to an atom's number of -

• A. positrons

• B. protons

• C. neutrons

• D. electrons

How many valence electrons does a neutral atom of silicon have?

• A. 3

• B. 4

• C. 5

• D. 6

Which student found the correct electron configuration for a neutral element of calcium?

• A. Student 1

• B. Student 2

• C. Student 3

• D. Student 5

Tags

NGSS.HS-PS1-1

Look at the image. A. heterogeneous mixture B. new solid C. toxic gas D. homogeneous mixture NaCl (s) dissolves A physical property of NaCl is when it is dissolved in water it forms a (s)

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NGSS.MS-PS1-2

Which element is a noble gas?

• A. Nitrogen (N)

• B. Xenon (Xe)

• C. Fluorine (F)

• D. Hydrogen (H)

Which of the following is a chemical change?

• A. Gasoline combusts in an engine.

• B. Copper metal is stretched into a long wire.

• C. Water is boiled on a stove.

• D. Salt is dissolved in water.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which subatance is the best conductor of heat and electricity?

• A. neon

• B. silver

• C. sulfur

• D. nitrogen

Tags

NGSS.HS-PS1-1

What does the atomic number of an element represent?

• A. the number of neutrons in its nucleus

• B. the number of particles in its nucleus

• C. the number of orbitals it has

• D. the number of protons in its nucleus