Which statement about atoms is false?

• An atom is the building block of matter.

• Atoms of different elements have the same number of protons.

• An atom has the properties of an element.

• An atom consists of smaller subatomic particles.

Which structure of the atom is represented by 5?

• neutron

• proton

• nucleus

• electron

How do particles with opposite charges interact?

• they attract each other

• they have no effect on each other

•  

  they remain neutral

• they repel each other

What is the difference between CO and Co?

• CO is an element, cobalt, and Co is a compound, carbon monoxide.

• CO and Co are both elements but with different atomic numbers.

• CO and Co are the same element with different representations

• CO is a compound, carbon monoxide, and Co is and element, cobalt.

Which elements are most commonly found in the chemistry of life?

•  

  S,P,O,N,C, and H

• S,P,O,N,C, and T

• C,H,O, and Cl

• S,P,O,Cl,C, and H

Which model represents a mixture?

• A

• B

• C

• B and C

Which of the following is an example of a pure substance?

• soil

• air

• aluminum

• saltwater

Which of the following is a compound?

• lemonade

•  

  helium

• gold

• water

Which of the following statements about elements is true?

• They can be broken down into simpler substances by chemical means.

• They consist of only one type of atom.

• They are always gases at room temperature.

• They always exist in the form of molecules.

Which of the following is a characteristic of a homogeneous mixture?

• Its components cannot be easily separated by chemical means.

• It has a uniform composition throughout

• It has a variable composition.

• Its components cannot be easily separated by physical means.