8th grade science trouble!!!!?

Question

I need the answers to these questions

1. Where would you expect to find the electrons of an atom with an atomic number of 7?

2. How do covalent bonds differ from Ionic bond?

3.Nails are formed from molten iron. Nails made of iron can rust after exposure to water and air. Which of these changes is an example of a physical change?

Answer 1

1. Where would you expect to find the electrons of an atom with an atomic number of 7?

Nitrogen? It is an atom of neutral charge, as I understand it (but check on this because I'm rusty), so the number of electrons=the atomic number.

Here's a link for the atomic model of Nitrogen. Hope this helps:

http://www.chemicalelements.com/elements/n.html


2. How do covalent bonds differ from Ionic bond?

A covelant bond occurs through the sharing of electrons. This sharing can be even or uneven. Covalent bonds occur to form molecules of nonmetals and creates a relatively strong bond.

Similarly, an ionic bond involves electrons, but the electrons are transferred (not shared) from one neutral atom (the giving atom or cation) to another (the taking atom or anion) then held together by an electrostatic charge resulting from the interaction of two oppositely charged ions. For this reason, an ionic bond can also be refered to as an electrocovelant bond. Ionic bonds create compounds and are a relatively weak form of bond.


3.Nails are formed from molten iron. Nails made of iron can rust after exposure to water and air. Which of these changes is an example of a physical change?

To form the nail by heating, shaping and cooling iron is a physical change. You physically heated it, you physically molded it and you physically cooled it--no change to the chemical makeup was made.

On the other hand, when iron experiences oxidation, etc. the iron is being chemically changed into a form of iron oxide coating or rust.

Answer 2

I will not do your homework for you, but I will help you find the answers.

1) He is asking where the electrons would be, as in how many electrons in each valence. (Hint: there will only be 2 valences in this atom, but how many electrons in each valence is what you get to find out.)

2) You can find this one very easily on wikipedia. It also has to do with the electrons in the outer valences. (Hint: one type of bonding donates, while the other shares. Which is which?)

3) This question makes no sense. You have only given us one example of physical change and yet the question reads like we are supposed to pick from a list of changes. But, just so you know, rusting IS a physical change, but also a chemical one (to get the specifics of this, check wikipedia). If "nails being formed by molten lava" is supposed to be another change on the list, it is purely a physical change with no chemical changes occuring. Now that I think about, this sounds like a trick question: your teacher may want to hear that rusting is chemical (though over time, it is also physical) and the nail forming is physical. I don't agree with that 100%, but I'm not the teacher.

Good luck.

Answer 3

1) Look on a periodic table

2) Look in this thing the size of a piece of paper that is quite thick, it's called a book, it'll have the answers in there, this is known as studying!

3)I'm pretty sure that rust is the physical change, in crystal structure anyway, look at a bar of Caduburys chocolate bar, it's solid/. Now bit a whole into a bar of Nestle Aero bar, it's all bubbly, this is what rust does to Iron when exposed to Oxygen. (Known as a honeycone structure)

Only reason I helped you out with the last part is that some nice guy helped me out on a Physics question and I might as well carry on the good-will. You're turn now!
The Physics question was a way harder than your question)

Answer 4

1..i'm confused on....i think they are asking for what orbital.....so fill up your orbitals. 2 in s1...2 in s2....6 in p2.........so yeah. sorta gave you the answer


2. As someone said, one shares electrons and one gives.

3. Melting the iron is a physical change. The structure is changing, but nothign about its chemical composition. Rust formation...although physical makes the nail look different, is a chemical change. The rust is iron oxide. Different compound than iron.

Answer 5

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Answer 6

I bet that if you open your textbook and read it, you'll find a section discussing the structure of atoms. That'll help you answer the first one.

There will also be a section that talks about chemical bonds and the differences between ionic and covalent bonds.

There will be yet another section that'll talk about chemical and physical changes.

READ and then THINK...That's the only way you'll learn...

Answer 7

1. The atom with the atomic # of 7 will be found to be Nitrogen (N) and is in the non-metals - the right upper area.

3. There is a color change.

Answer 8

These are all very basic questions, and you don't know the answers? Get off the computer and study harder or you will be making french fries at the local truck stop for the rest of your life.

Answer 9

that's 8 grade science? wow! i'm in high skool now n i never learn that. when u get the ans plz tell me! thx!