A chemist is identifying the elements found in a sample of pond water. What characteristic of an element's atoms always determines the identity of the element?

• Number of protons

• Number of neutrons

• Location of valence electrons

• Number of valence electrons

How many valence electrons are in an atom of each element in Group 13 in the Periodic Table?

• 13

• 3

• 10

• 5

What is the mass number of a carbon (C) atom that has 8 neutrons?

• 12

• 12.011

• 14

• 14.011

An atom has 82 protons, 125 neutrons, and 82 electrons. What is the charge of the atom's cloud?

• +82

• -82

• +125

• 0

Which element is found in Group 2, period 2 of the periodic table?

• boron

• barium

• beryllium

• bismuth

Tags

NGSS.MS-PS1-1

Which element has an atomic mass of 20?

• neon

• nickel

• nitrogen

• sodium

Tags

NGSS.MS-PS1-1

Which of the following elements is the least reactive?

• bromine

• chlorine

• fluorine

• iodine

Tags

NGSS.MS-PS1-2

How many neutrons are there in an atom of potassium?

• 19

• 20

• 39

• 58

Which of the following elements will not form positive ions when it reacts?

• chlorine

• lithium

• magnesium

• silver

Tags

NGSS.MS-PS1-2

Copper exists naturally as two isotopes, 63Cu and 65Cu. The abundance of 63Cu is 69% and the abundance of 65Cu is 31%. What is the relative atomic mass of copper to 3 significant figures?

• 63.3

• 63.6

• 64.3

• 64.4

Tags

NGSS.MS-PS1-1