Which best explains how atoms combine to from compounds?

• The atoms in the compounds share electrons.

• The atoms in the compound share neutrons

• The atoms in the compounds share protons

Which element is in the same family as Chlorine(Cl) and Fluorine (F)?

• hydrogen (H)
• Lithium (Li)
• Oxygen (O)
• Bromine (Br)
  

Sodium (Na), lithium(Li), and potassium (K) are grouped together. Which property do they share?

• soft texture
• high reactivity
• semiconductivity 
• gas at room temperature

When elements chemically combine, which best describes the resulting compound?

• It has different ratios of atoms
• It has different types of matter
• It has the same properties as the uncombined elements 
• It has different properties from the uncombined elements 
  

Tags

NGSS.MS-PS1-1

How many atoms are in one formula unit of magnesium hydroxide, Mg(OH)₂?

• 6
• 5
• 4
• 3

Tags

NGSS.MS-PS1-1

When burning methane gas, which outcome best demonstrates the law of conservation of mass?

• CH₄→CO₂+ H₂O
• CH₄ + O₂ → CO₂ + 2H₂O
• CH₄ + O₂ → CO₂ + 2H₂O
  
• CH₂ + 2O₂ → CO₂+ 2H2O

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Where are the most reactive metals located on the periodic table? 

• the uppermost complete row of the table
• the rows at the bottom of the table connecting two section
• the column at the far left side of the table
• the second column from the right side of the table
  

Sodium reacts with water. Which element is most likely  to have a similar effect to sodium ?

• Carbon 
• Oxygen 
• Lithium

Which property is unique for each element?

• Mass Number
• Atomic Number
• State of Matter

What do the atomic numbers represent?

• number of atoms 
• number of protons
• number of neutrons

Tags

NGSS.HS-PS1-7