# An atom has 18 protons, 18 electrons, and 20 neutrons. This atom has _____. A.) a negative charge B.) a positive charge C.) a mass number of 38 D.) an atomic number of 20

QUESTION POSTED AT 13/02/2020 - 10:00 PM

### Answered by admin AT 13/02/2020 - 10:00 PM

an atom that has 18 protons, 18 neutrons and 20 neutrons. This atom has mass number of 38

mass number is calculated as number of protons + number on neutrons

therefore the mass number of the atom = 18+20= 38

Since the atom has a electronic configuration of 2.8.8,the atom cannot be negatively or positively charged because it is stable.

The atomic number of the atom is 18 since atomic number is equal to number of protons

## Related questions

### The correct answer is c. Energy processing from corn biofuels is not energy efficient.

Exellent!!!!!!!!!!!!!!

ANSWERED AT 28/02/2020 - 05:17 PM

QUESTION POSTED AT 28/02/2020 - 05:17 PM

### Classify this statement as always true, AT; sometimes true, ST; or never true, NT. To obtain a value for the number of moles using the ideal gas law, one uses the conditions of STP.

AT, STP in chemistry is the abbreviation for Standard Temperature and Pressure. STP most commonly is used when performing calculations on gases, such as gas density

ANSWERED AT 28/02/2020 - 05:11 PM

QUESTION POSTED AT 28/02/2020 - 05:11 PM

### Why do electrons in a copper penny not fly out?

Copper is a good conductor because, like other metals, it contains free electrons. Free electrons are also known as conduction electrons. Each copper atom provides a single free electron, so there are as many free electrons as atoms.

Free electron concentration in copper n = 8.5 × 1028 per m3

When a voltage is connected across a piece of copper, it pushes the free electrons so that they flow through the metal – that's an electric current.

Interactive graphic of electrical conduction
Interactive graphic of electrical conduction

Picture 3.4 Close the switch to apply voltage: electrons start to flow through. Increase the voltage and they drift faster.

Notice that the electrons start to flow as soon as the switch is closed. The message to get them moving is instantaneous (in fact it travels close to the speed of light). However, the electrons themselves travel much more slowly. So how does the current come on everywhere as soon as the switch is closed?
It is because the free electrons are already spread through the wire. As soon as the switch is closed, there is a force on all the electrons, which gets them moving. It's a bit like a bicycle chain. As soon as you start pedalling, the back wheel starts to turn. The force on the back wheel is instantaneous even though the individual links are travelling at a visible speed. But because the links are already spread around the chain 'circuit' they all start to move at the same time.

Electron velocities

The animation above is slightly deceptive because it shows the electrons as being stationary when there is no voltage.
In reality, even when no current flows through a piece of copper, the free electrons are moving rapidly about. Their speed is about 106 m s-1; that's 3000 times the speed of sound in air! However, since they are moving at random, there is no net flow of electrons in any particular direction and so there is no current.

When a voltage is applied, the electrons gain an additional velocity, so that there is a net flow along the wire. This extra velocity is called their drift velocity. Here's a way to picture this:

ANSWERED AT 28/02/2020 - 05:05 PM

QUESTION POSTED AT 28/02/2020 - 05:05 PM

### According to recent research, ice skaters are able to glide smoothly across the ice because A. ice is constantly subliming to form a layer of water vapor B. a thin, liquid-like layer of water covers the ice C. pressure from the skates raises the melting point of ice D. pressure from the skates lowers the melting point of ice

B. A thin, liquid-like layer of water covers the ice

Explanation:

Hello,

Ice skaters are able to glide smoothly across the ice because a thin, liquid-like layer of water covers the ice, this is achieved due to the environmental conditions which allow the liquid water layer to coexist with the ice. Due to this fact, the liquid-like layer diminishes the friction coefficient between the ice skateboard and the ice allowing the slip to be carried out smoothly.

Best regards.

ANSWERED AT 28/02/2020 - 05:05 PM

QUESTION POSTED AT 28/02/2020 - 05:05 PM

### What is the ph of a neutral solution at 25°c?

pH = 7.00

Explanation:

In water at 25 °C,

The solution is neutral, so

To get the pH, you take the negative logarithm of the hydronium ion concentration.

ANSWERED AT 28/02/2020 - 05:03 PM

QUESTION POSTED AT 28/02/2020 - 05:03 PM

### How many protons neutrons and electrons does nitrogen 14 have?

Many nitrogen atoms have seven neutrons (14-7 = 7). Some atoms of nitrogen, however, have eight electrons. They are atoms of N-15, an isotope of nitrogen. In a neutral atom, the number of protons must equal the number of electrons.

ANSWERED AT 28/02/2020 - 04:57 PM

QUESTION POSTED AT 28/02/2020 - 04:57 PM

### What is the molarity of a solution of kno3 (molecular mass = 101 that contains 404 grams of kno3 in 2.00 liters of solution? a 1.00 b 2.00 c 0.500 d 4.00?

(1 mol KNO3/ 101 g KNO3)(404 g KNO3)= 4 moles
D

ANSWERED AT 28/02/2020 - 04:37 PM

QUESTION POSTED AT 28/02/2020 - 04:37 PM

### Mixing 25.0 ml of 1.2 m hclo4 and 25.0 ml of 1.1 m naoh were mixed. the temperature of the initial solution was 22.4 o c. assuming a heat of neutralization of 55.8 kj/mol, what would the final temperature be if the specific heat for this solution is 4.032 j/g o ?

I think its
22.4C + 7.6C = 30.0C

ANSWERED AT 28/02/2020 - 04:35 PM

QUESTION POSTED AT 28/02/2020 - 04:35 PM

### A sample of hydrogen has an initial temperature of 50.° c. when the temperature is lowered to -5.0° c, the volume of hydrogen becomes 212 cm3 . what was the initial volume of the hydrogen in dm3?

Using the
V1/T1=V2/T2
where
T1=50C= 323.15K
T2= -5C=268.15 K
V2= 212m^3
substitute the given values, we will get the initial volume
V1=V2T1/T2
V1= 255.48m^3

The initial volume is 255.48m^3

ANSWERED AT 28/02/2020 - 04:31 PM

QUESTION POSTED AT 28/02/2020 - 04:31 PM

### A certain vinegar is 6.02% acetic acid (hc2h3o2, by mass. how many grams of acetic acid are contained in a 355 ml bottle of vinegar. assume a density of 1.01 g/ml.

First, determine the amount of vinegar in grams by multiplying the volume by the density. That is,
mass = (355 ml) x (1.01 g/mL) = 358.55 g
Then, multiply the calculated mass above by the decimal equivalent of the given percentage above.
amount of acetic acid = (358.55 g)(0.0602) = 21.58 g

ANSWERED AT 28/02/2020 - 04:11 PM

QUESTION POSTED AT 28/02/2020 - 04:11 PM

### Nuclear energy is produced when scientists force uranium (U) atoms to break apart. With this in mind, examine the list below. If scientists were to break apart each of the items on the list, which items would still be classified in the same way? Which items would be classified differently? • atoms • elements • compounds • molecules • matter

Compound.

Explanation:

A compound is a made up of two or more than two different elements. It can be broken down into smaller molecules.Elements are combined to form a compound by chemical bonding like ionic bonding and covalent bonding.

Different compounds of different elements can be broken down into the chemical reaction called decomposition reaction. For example:

Using electrolysis, we can break down water into its elements hydrogen and oxygen.

ANSWERED AT 28/02/2020 - 04:06 PM

QUESTION POSTED AT 28/02/2020 - 04:06 PM

### What is the net ion charge of beryllium? +2 -2 +1 -1

+2

Explanation:

ANSWERED AT 28/02/2020 - 04:01 PM

QUESTION POSTED AT 28/02/2020 - 04:01 PM

### An atom of an element has 28 innermost electrons and 7 outermost electrons. In which period of the Periodic Table is this element located? 1. 5 2. 2 3. 3 4. 4

Answer: The given element belongs to Period 4.

Explanation:

We are given:

Number of innermost electrons = 28

Number of outermost electrons = 7

Total number of electrons = 28 + 7 = 35

Electronic configuration is defined as the representation of electrons around the nucleus of an atom.

Number of electrons in an atom is determined by the atomic number of that atom.

The electronic configuration of the element having atomic number '35' is:

To identify the period, we look at the highest occupied principle quantum number which is 'n'. Here, the value of highest occupied shell or 'n' is 4.

Hence, the given element belongs to Period 4.

ANSWERED AT 28/02/2020 - 03:57 PM

QUESTION POSTED AT 28/02/2020 - 03:57 PM

### The modern model of the atom used today is the Plum Pudding model. true or false

That would be false.

ANSWERED AT 28/02/2020 - 03:42 PM

QUESTION POSTED AT 28/02/2020 - 03:42 PM

### If a car travels from Town A to Town B on one road at different speeds and stops at red lights, knowing the distance between the towns and the total time of the trip can allow you to calculate A. average velocity. B. instantaneous velocity. C. deceleration. D. uniform velocity

A. Average velocity is correct.

ANSWERED AT 28/02/2020 - 03:41 PM

QUESTION POSTED AT 28/02/2020 - 03:41 PM

### Write the symbol for every chemical element that has atomic number less than 74 and atomic mass greater than 173.8u

You should be able to locate them on the periodic table as long as you know which part the atomic number is and which part the atomic mass is.

ANSWERED AT 28/02/2020 - 03:22 PM

QUESTION POSTED AT 28/02/2020 - 03:22 PM

### The atom is the basic unit in chemistry. An atom contains neutrons, protons, and electrons. Neutrons are neutral, protons have a positive charge, and electrons have a negative charge. Most of the time, atoms are neutrally charged, meaning that they have the same number of protons and electrons. Sometimes, though, atoms lose or gain one or more electrons, and become positively or negatively charged. A positively or negatively charged atom is called an ion. An ion with more protons than electrons is positively charged. An ion with more electrons than protons is negatively charged. One common ion is a Sodium ion, which has a charge of +1. Which of the following statements is true? The ion has more protons than electrons. The ion has the same number of protons and electrons. The ion has more electrons than protons.

The ion has more electrons than protons. For sure

ANSWERED AT 28/02/2020 - 03:08 PM

QUESTION POSTED AT 28/02/2020 - 03:08 PM

### Chloroform is not soluble in water. The normal freezing point of chloroform is 63.5°C. The normal freezing point of water is 0.0°C. What would the freezing point of water be if 10 milliliters of water were mixed with 10 milliliters of chloroform?

You should test it out and see the aswer

ANSWERED AT 28/02/2020 - 02:55 PM

QUESTION POSTED AT 28/02/2020 - 02:55 PM

### During a chemical reaction, _______ and _______ are both conserved. a. mass; electricity b. weight; electricity c. mass; energy d. weight; energy

The answer is C mass and energy

ANSWERED AT 28/02/2020 - 02:55 PM

QUESTION POSTED AT 28/02/2020 - 02:55 PM

### A mole is the amount of a substance that contains as many particles as the number of atoms in 12 grams of what isotope?

The SI unit for amount of substance is the mole. It has the unit symbol mol. The proportionality constant is the inverse of the Avogadro constant. The mole is defined as the amount of substance that contains an equal number of elementary entities as there are atoms in 12g of the isotope carbon-12.

Hope This Helped! :3

ANSWERED AT 28/02/2020 - 02:51 PM

QUESTION POSTED AT 28/02/2020 - 02:51 PM

### A mole is the amount of a substance that contains as many particles as the number of atoms in 12 grams of what isotope?

The 12C isotope.  Hope this helps.

ANSWERED AT 28/02/2020 - 02:51 PM

QUESTION POSTED AT 28/02/2020 - 02:51 PM

### The specific heat of nickel is 0.44 J/g*⁰C. How much energy needed to change the temperature of 95.4g of nickel from 22⁰C to 32⁰C. Is the energy absorbed or released?

Answer : The amount of energy needed is, 419.76 J and the energy is absorbed.

Solution :

Formula used :

where,

Q = heat gained or absorbed = ?

m = mass of nickel = 95.4 g

c = specific heat of nickel =

= final temperature =

= initial temperature =

Now put all the given values in the above formula, we get

The value of Q is positive that means energy is absorbed.

Therefore, the amount of energy needed is, 419.76 J and the energy is absorbed.

ANSWERED AT 28/02/2020 - 02:51 PM

QUESTION POSTED AT 28/02/2020 - 02:51 PM

### Who first arranged the elements according to nuclear charge?

dmitri Medeleev is the man

ANSWERED AT 28/02/2020 - 02:47 PM

QUESTION POSTED AT 28/02/2020 - 02:47 PM

### Which of the following actions will stop an induced current in a wire wrapped around a magnet? A.reducing number of coils in the wire B.increasing the magnet strength C.removing the battery from the circuit D.keeping the magnet stationary

A. Reducing number of coils in the wire

ANSWERED AT 28/02/2020 - 02:41 PM

QUESTION POSTED AT 28/02/2020 - 02:41 PM

### In what phase of matter do particles fill the entire container in which their placed? A. Liquid B. Gas C. Solid D. Frozen

gas

Explanation:

ANSWERED AT 28/02/2020 - 02:39 PM

QUESTION POSTED AT 28/02/2020 - 02:39 PM

### Which of these statements is false? A. The color we see for any object is color that is reflected from it. B. The primary colors of pigment mix to make white. C. The primary colors of light mix to make white. D. White light is made of all colors.

The Answer is C The primary colors of light mix to make white

ANSWERED AT 28/02/2020 - 02:36 PM

QUESTION POSTED AT 28/02/2020 - 02:36 PM

### Which of the phases below are NOT able to be compressed A. Solid only B. Liquid only C. Gas and Liquid D. Solid and liquid

Solid only, you can compress a liquid VERY little but it can be compressed.

ANSWERED AT 28/02/2020 - 02:31 PM

QUESTION POSTED AT 28/02/2020 - 02:31 PM

### How manyy grams of h2 are needed to react with 20 grams of o2. please show work

Would it be 10, you know 1h for every 2o, H2O

ANSWERED AT 28/02/2020 - 02:28 PM

QUESTION POSTED AT 28/02/2020 - 02:28 PM

### Which of the following compounds would be named with a name that ends in -yne? A. CH3-CH2-CH3 B. CH3-CH(double bond)CH-CH3 C. CH(triple bond)C-CH2-CH3 D. CH3-CH2-CH2-CH(double bond)CH2

ANSWERED AT 28/02/2020 - 02:28 PM

QUESTION POSTED AT 28/02/2020 - 02:28 PM