Atoms of which two elements have a combined total of 23 protons?

• Sodium, Na, and magnesium, Mg

• Boron, B, and carbon, C

• Copper, Cu, and zinc, Zn

• None of these

A scientist performs tests on a sample of an element. The element is a shiny solid that conducts electricity and heat. The scientist is able to bend and flatten the sample when

pressure is applied to it.

Based on this information, the element could NOT be a member of which group on the

periodic table?

• Group 2

• Group 8

• Group 12

• Group 18

The atomic number of krypton is 36. If the mass number of a krypton atom is 84, which answer shows the number of subatomic particles inside and outside the nucleus of the krypton atom?

• Number of Particles Inside Nucleus 36

  Number of Particles Outside Nucleus 36

• Number of Particles Inside Nucleus 36

  Number of Particles Outside Nucleus 48

• Number of Particles Inside Nucleus 84

  Number of Particles Outside Nucleus 36

• Number of Particles Inside Nucleus 84

  Number of Particles Outside Nucleus 48

Tags

NGSS.MS-PS1-1

The diagram shows a model of an atom. The model has four different symbols on it. Each symbol represents a different role for one of the particles within the atom. In this model, which particle determines the reactivity of this atom?

• Particle W

• Particle X

• Particle Y

• Particle Z

Tags

NGSS.MS-PS1-1

Element R and Element Q have the same number of valence electrons. These elements 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?

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

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

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

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

Tags

NGSS.MS-PS1-1

Four students were asked to name the parts of an atom that determine the atom’s identity and chemical properties. The students’ responses are shown in the table. Which student’s responses are correct?

• student 1

• student 2

• student 3

• student 4

Tags

NGSS.MS-PS1-1

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

• 72 protons, 178 neutrons, 106 electrons

• 72 protons, 106 neutrons, 72 electrons

• 178 protons, 250 neutrons, 72 electrons

• 106 protons, 72 neutrons, 106 electrons

Tags

NGSS.MS-PS1-1

Tin, Sn, is a soft white metal. It has a low melting point compared with other metals. Tin is widely used as a coating for cans of food. Which statement accurately describes atoms of tin?

• Tin atoms have 50 protons.

• Tin atoms have five valence electrons.

• Tin atoms have 119 neutrons.

• Tin atoms have 68 electrons.

Tags

NGSS.MS-PS1-1

An element's identity is determined by the number of

• electrons.
• protons.
• neutrons.
• valence.

How many Valance electrons does Iodine Have?

• 6
• 16
• 7
• 17