Periods & Groups

How many protons, neutrons and electrons are present in an atoms of hafnium, Hf, with a mass number of 178?

• A - 72protons, 178 neutrons, 106 electrons

• B - 178 protons, 250 neutrons, 72 electrons

• C- 106 protons, 72 neutrons, 106 electrons

• D - 72 protons, 178 neutrons, 106 electrons

Tags

NGSS.MS-PS1-1

An atom has 25 protons, 30 neutrons and 25 electrons. What is the atomic mass of the atom?

• R - 30

• S - 25

• T - 55

• U - 50

A student is studying the ways different elements are similar to one another. Diagrams of atoms from four elements are shown above. Which two atoms are of elements in the same group of the periodic table?

• L - Atom 3 and Atom 4

• M - Atom 2 and Atom 3

• N - Atom 1 and Atom 2

• O - Atom 1 and Atom 4

Tags

NGSS.MS-PS1-1

Which two elements on the periodic table are in the same period?

• L - Se and Te

• M - SN and Rb

• N - K and Ba

• O - F and Cl

Element R and Element Q have the same number of valence electrons. These elemetns both have similar chemical behavior, but Element R has fewer energy levels than Element Q. Which statement best describes the positions of the two elements in the periodic table?

• R - The two elements are in the same period, with Element R the first element in the period and Element Q the last element.

• S - The two elements are in the same group, with Element R just above Element Q.

• T - The two elements are in the same group, Element Q at the top of the group and Element R at the bottom.

• U - The two elements are side by side in the same period, with Element Q to the left of Element R.

Tags

NGSS.MS-PS1-1