Well, I tried

ChemicalReactor.cpp

class ChemicalElement {
private:
	float a;
	int z;

	bool _isMetal;

	int period;
	int group;
	bool main;
	std::string name; // Sodium
	std::string sign; // Na
public:

	ChemicalElement() {
	}

	ChemicalElement(std::string name) {
		this->name = name;
	}

	ChemicalElement(float a, int z, int group, int period, bool main, bool metal, std::string name, std::string sign) {
		this->group = group;
		this->period = period;
		this->_isMetal = metal;
		this->main = main;

		this->a = a;
		this->z = z;
		this->sign = sign;
		this->name = name;
	}

	bool isMetal() {
		return this->_isMetal;
	}

	int getPeriod() {
		return this->period;
	}

	int getGroup() {
		return this->group;
	}

	bool isMain() {
		return this->main;
	}

	std::string getName() {
		return this->name;
	}

	std::string getSign() {
		return this->sign;
	}

	int getZ() {
		return this->z;
	}

	int getA() {
		return this->a;
	}
};

namespace PeriodicTable {
	std::vector<ChemicalElement*> elements;
	std::map<std::string, int> indicies;

	void add(ChemicalElement* el) {
		indicies[el->getSign()] = elements.size();
		elements.push_back(el);
	}

	void init() {
		add(new ChemicalElement(1, 1, "Hydrogen", "H"));
		add(new ChemicalElement(14, 7, "Nitrogen", "N"));
		add(new ChemicalElement(16, 8, "Oxygen", "O"));
		add(new ChemicalElement(19, 9, "Fluorine", "F"));
		add(new ChemicalElement(23, 11, "Sodium", "Na"));
		add(new ChemicalElement(39, 19, "Potassium", "K"));
		add(new ChemicalElement(35.5f, 17, "Chlorine", "Cl"));
		add(new ChemicalElement(107.8f, 47, "Silver", "Ag"));
	}

	ChemicalElement* getBySign(std::string name) {
		std::cout << "[DEBUG] " << name << std::endl;

		return elements[indicies[name]];
	}

	ChemicalElement* getByName(std::string sign) {
		for (int i = 0; i < elements.size() && elements[i]->getName() != sign; ++i) {
			return elements[i];
		}
	}

	ChemicalElement* getByZ(int z) {
		for (int i = 0; i < elements.size() && elements[i]->getZ() != z; ++i) {
			return elements[i];
		}
	}
}

class Ion {
private:
	int charge;
	ChemicalElement* element;
	const std::regex ionRegex = std::regex("(?:\\w)*(\\+|\\-[0-9]*)");
	std::string textual;

	void parse(std::string str) {
		std::smatch result;
		std::regex_search(str, result, ionRegex);

		if (result[1] == "-") {
			this->charge = -1;
		}
		else if (result[1] == "+") {
			this->charge = 1;
		}
		else {
			this->charge = std::stoi(result[1]);
		}

		this->element = PeriodicTable::getBySign(str.substr(0, str.length() - str.find(result[1]) + 1));
	}
public:
	// OH- -> O, H, charge = -1
	// NO3- -> N, O, charge = 
	// Ag+
	Ion(std::string str) {
		this->textual = str;
		this->parse(str);

		std::cout << "Hello, I'm " << this->element->getName() << " I have charge: " << this->charge << std::endl;
	}
};

class Molecule {
private:
	std::vector<ChemicalElement*> elements;
	const std::regex expression = std::regex("(?:\\w)*(\\+|\\-[0-9]*)");
	std::string textual;

	void parse() {
		std::string atoms = str.substr(0, str.length() - str.find(result[1]) + 1);

		std::cout << str << " " << result[1] << std::endl;
		std::cout << "Atoms: " << atoms << std::endl;


		// NaCl
		// Ca(OH)2
		// Na[Al(OH)4]
		// (NH4)2SO4

		int i = 0;
		int j = -1;
		std::string temp;

		while (atoms[i]) {
			char current = atoms[i];

			temp += current;

			if (isupper(current)) {
				if (j != -1) {
					//this->elements.push_back(PeriodicTable::getBySign(temp));

					std::cout << temp;
					temp = "";
				}

				j = i;
			}

			++i;
		}
	}
public:
	
};

class Reactor {
private:

};