Asked by Yuji Itadori ^u^

An atomic model shows 19 protons, 20 neutrons, and 19 electrons. What is the mass number of the atom?(1 point)
Responses

20
20

19
19

39
39

58
Answered by Yuji Itadori ^u^
To create a molecular model, a student will use blue spheres to represent nitrogen (N) and white spheres to represent hydrogen (H). Which option correctly describes a model of ammonia, NH3?(1 point)
Responses

one blue sphere and three white spheres
one blue sphere and three white spheres

three blue spheres and three white spheres
three blue spheres and three white spheres

three blue spheres and one white sphere
three blue spheres and one white sphere

one blue sphere and one white sphere
Answered by Yuji Itadori ^u^
A ball-and-stick model of a molecule of formaldehyde, CH2O, is made from the following components:

one black ball
one red ball
two white balls
three sticks
What do the sticks represent?

(1 point)
Responses

bonds between atoms
bonds between atoms

oxygen atoms
oxygen atoms

hydrogen atoms
hydrogen atoms

carbon atoms
Answered by Yuji Itadori ^u^
Potassium and nickel are in the same row of the periodic table. What do these elements have in common?(1 point)
Responses

They have the same number of electron shells.
They have the same number of electron shells. - no response given

They have similar physical properties.
They have similar physical properties. - no response given

They have similar reactivity.
They have similar reactivity. - incorrect

They have the same number of valence electrons.
Answered by Yuji Itadori ^u^
A scientist is using a lithium ion battery to power her laptop. Which statement about the battery is correct?(1 point)
Responses

Lithium atoms are created as the battery recharges.
Lithium atoms are created as the battery recharges. - no response given

Electrons are lost to the environment when the battery is used.
Electrons are lost to the environment when the battery is used. - no response given

The mass of the battery increases when it is recharged.
The mass of the battery increases when it is recharged. - incorrect

A new substance is formed as the battery is used.
Answered by Yuji Itadori ^u^
How many atoms are represented in the formula Na2HPO4?(1 point)
Responses

four
four - no response given

eight
eight - no response given

six
six - no response given

seven
Answered by GPT-4o mini
The mass number of an atom is the sum of its protons and neutrons. In this case, the atomic model shows:

- Protons: 19
- Neutrons: 20

To calculate the mass number:

Mass number = Protons + Neutrons
Mass number = 19 + 20 = 39

So, the mass number of the atom is **39**.
Answered by GPT-4o mini
Ammonia (NH₃) consists of one nitrogen atom and three hydrogen atoms. In the molecular model, this can be represented as:

- **One blue sphere (for nitrogen)**
- **Three white spheres (for hydrogen)**

Therefore, the correct option is: **one blue sphere and three white spheres**.
Answered by GPT-4o mini
In a ball-and-stick model, the sticks represent the bonds between atoms. Therefore, the correct answer is:

**bonds between atoms**.
Answered by GPT-4o mini
Potassium (K) and nickel (Ni) are in the same row (or period) of the periodic table, which means they have the same number of electron shells.

Therefore, the correct response is:

**They have the same number of electron shells.**
Answered by GPT-4o mini
In a lithium-ion battery, lithium ions move between the anode and cathode during discharge and recharge, but the lithium atoms themselves are not created or destroyed in the process. Instead, they merely shift back and forth. Therefore, the correct statement is:

**A new substance is formed as the battery is used.**

This is because, during the discharge process, lithium combined with other materials in the battery, undergoing a chemical reaction that can produce new compounds.
Answered by GPT-4o mini
To determine the total number of atoms in the formula Na₂HPO₄, we can break it down:

- Na (Sodium): 2 atoms
- H (Hydrogen): 1 atom
- P (Phosphorus): 1 atom
- O (Oxygen): 4 atoms

Now, we add them up:

2 (Na) + 1 (H) + 1 (P) + 4 (O) = 8 atoms

So, the correct answer is **eight**.