STAAR Sci Category 1

An atom of an element has 36 protons, 36 electrons, and a mass number of 84? How many neutrons?

• 36

• 72

• 48

• 8

Tags

NGSS.MS-PS1-1

What types of particles are found in the cloud surrounding the atom's nucleus?

• positively and negatively charged particles

• negatively charged particles only

• neutral and positively charged particles

• positively charged particles only

Which of the following is the best description of an electron?

• No charge and the same mass as a proton

• negative charge and much less mass than a proton

• positive charge and much more mass than a neutron

• negative charge and the same mass of a neutron

Tags

NGSS.MS-PS2-3

Atoms of a certain element have 11 protons and 1 valence electron. Which statement is correct?

• the element is sodium and it is not reactive

• the element is fluorine and it is highly reactive

• the element is fluorine and it is not reactive

• the element is sodium and it is highly reactive

Tags

NGSS.MS-PS1-1

What characteristic of an atom always determines it's identity?

• number of neutrons

• number of protons

• number of valence electrons

• location of valence electrons

Which characteristic of calcium is most closely related to its chemical reactivity?

• 20 protons in each calcium atom

• calcium's density is 1.54 g.cm³

• 2 valence electrons in each atom of calcium

• one calcium atom has an atomic mass of 40.078 amu

Tags

NGSS.MS-PS1-5

Which two elements are in the same period?

• F and Cl

• Sn and Rb

• K and Ba

• Se and Te

Which process is the best example of a physical change in the digestive system?

• saliva converting starch molecules into simple sugar

• digestive enzymes breaking down proteins into smaller parts

• intestinal bacteria converting lactose into simple sugars

• teeth grinding an almond into smaller pieces in the mouth

6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂

How many oxygen atoms in total are present in the reaction?

• 10

• 21

• 12

• 18

Tags

NGSS.MS-PS1-5

6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂

How many carbon atoms in total are present in the reaction?

• 6

• 18

• 12

• 10

Tags

NGSS.MS-PS1-1